Collagen - Knowledge (XXG)

142: 1140: 1537:. These later advances are particularly important to better understanding the way in which collagen structure affects cell–cell and cell–matrix communication and how tissues are constructed in growth and repair and changed in development and disease. For example, using AFM–based nanoindentation it has been shown that a single collagen fibril is a heterogeneous material along its axial direction with significantly different mechanical properties in its gap and overlap regions, correlating with its different molecular organizations in these two regions. 213: 1509:(a unit that is referred to as 'D' and changes depending upon the hydration state of the aggregate). In each D-period repeat of the microfibril, there is a part containing five molecules in cross-section, called the "overlap", and a part containing only four molecules, called the "gap". These overlap and gap regions are retained as microfibrils assemble into fibrils, and are thus viewable using electron microscopy. The triple helical tropocollagens in the microfibrils are arranged in a quasihexagonal packing pattern. 2713: 1513: 1040:. The reaction consumes one ascorbate molecule per hydroxylation. The synthesis of collagen occurs inside and outside of a cell. The formation of collagen which results in fibrillary collagen (most common form) is discussed here. Meshwork collagen, which is often involved in the formation of filtration systems, is another common form of collagen. All types of collagens are triple helices, and the differences lie in the make-up of their alpha peptides created in step 2. 1419: 33: 1335: 951: 503: 2838: 2930: 2974:, are marketed to improve skin, hair, and nails. Studies show some skin benefits, but these supplements often contain other beneficial ingredients, making it unclear if collagen alone is effective. There's minimal evidence supporting collagen's benefits for hair and nails. Overall, the effectiveness of oral collagen supplements is not well-proven, and focusing on a 1442:, where X may be any of various other amino acid residues. Proline or hydroxyproline constitute about 1/6 of the total sequence. With glycine accounting for the 1/3 of the sequence, this means approximately half of the collagen sequence is not glycine, proline or hydroxyproline, a fact often missed due to the distraction of the unusual GX 1110:: In the Golgi apparatus, the procollagen goes through one last post-translational modification before being secreted out of the cell. In this step, oligosaccharides (not monosaccharides as in step 3) are added, and then the procollagen is packaged into a secretory vesicle destined for the extracellular space. 2351:– Thirteen different types of this disorder, which lead to deformities in connective tissue, are known. Some of the rarer types can be lethal, leading to the rupture of arteries. Each syndrome is caused by a different mutation. For example, the vascular type (vEDS) of this disorder is caused by a mutation in 443:

As the skeleton forms the structure of the body, it is vital that it maintains its strength, even after breaks and injuries. Collagen is used in bone grafting as it has a triple helical structure, making it a very strong molecule. It is ideal for use in bones, as it does not compromise the structural

1098:

Once these modifications have taken place, three of the hydroxylated and glycosylated propeptides twist into a triple helix forming procollagen. Procollagen still has unwound ends, which will be later trimmed. At this point, the procollagen is packaged into a transfer vesicle destined for the Golgi

562:

Collagen is a natural product and is thus used as a natural wound dressing and has properties that artificial wound dressings do not have. It is resistant against bacteria, which is of vital importance in a wound dressing. It helps to keep the wound sterile, because of its natural ability to fight

452:

Collagen scaffolds are used in tissue regeneration, whether in sponges, thin sheets, gels, or fibers. Collagen has favorable properties for tissue regeneration, such as pore structure, permeability, hydrophilicity, and stability in vivo. Collagen scaffolds also support deposition of cells, such as

1480:

are lower than most warm-blooded animals. Lower proline and hydroxyproline contents are characteristic of cold-water, but not warm-water fish; the latter tend to have similar proline and hydroxyproline contents to mammals. The lower proline and hydroxyproline contents of cold-water fish and other

1540:

Collagen fibrils/aggregates are arranged in different combinations and concentrations in various tissues to provide varying tissue properties. In bone, entire collagen triple helices lie in a parallel, staggered array. 40 nm gaps between the ends of the tropocollagen subunits (approximately

1524:

crosslinking within the triple helices and a variable amount of covalent crosslinking between tropocollagen helices forming well-organized aggregates (such as fibrils). Larger fibrillar bundles are formed with the aid of several different classes of proteins (including different collagen types),

1470:

Because glycine is the smallest amino acid with no side chain, it plays a unique role in fibrous structural proteins. In collagen, Gly is required at every third position because the assembly of the triple helix puts this residue at the interior (axis) of the helix, where there is no space for a

1458:

Collagen is not only a structural protein. Due to its key role in the determination of cell phenotype, cell adhesion, tissue regulation, and infrastructure, many sections of its non-proline-rich regions have cell or matrix association/regulation roles. The relatively high content of proline and

2491:

of collagen at the molecular level. Only above a certain strain rate is there a strong relationship between elastic modulus and strain rate, possibly due to the large number of atoms in a collagen molecule. The length of the molecule is also important, where longer molecules have lower tensile

2513:

is often chosen as the ideal material because it is close to a pure and aligned collagen structure. However, at the macro, tissue scale, the vast number of structures that collagen fibers and fibrils can be arranged into results in highly variable properties. For example, tendon has primarily

3006:

The packing structure of collagen has not been defined to the same degree outside of the fibrillar collagen types, although it has been long known to be hexagonal. As with its monomeric structure, several conflicting models propose either that the packing arrangement of collagen molecules is

1450:

character of collagen alpha-peptides. The high glycine content of collagen is important with respect to stabilization of the collagen helix as this allows the very close association of the collagen fibers within the molecule, facilitating hydrogen bonding and the formation of intermolecular

1091:

Hydroxylation of lysines and prolines on propeptide by the enzymes 'prolyl hydroxylase' and 'lysyl hydroxylase' (to produce hydroxyproline and hydroxylysine) occurs to aid cross-linking of the alpha peptides. This enzymatic step requires vitamin C as a cofactor. In scurvy, the lack of

641:

The collagen protein is composed of a triple helix, which generally consists of two identical chains (α1) and an additional chain that differs slightly in its chemical composition (α2). The amino acid composition of collagen is atypical for proteins, particularly with respect to its high

2371:

gene that codes for the production of collagen XVIII. Patients present with protrusion of the brain tissue and degeneration of the retina; an individual who has family members with the disorder is at an increased risk of developing it themselves since there is a hereditary link.

2361:– Can be passed on genetically, usually as X-linked dominant, but also as both an autosomal dominant and autosomal recessive disorder, those with the condition have problems with their kidneys and eyes, loss of hearing can also develop during the childhood or adolescent years. 398:

of blood pressure emitted from the heart. The collagenous structure that divides the upper chambers of the heart from the lower chambers is an impermeable membrane that excludes both blood and electrical impulses through typical physiological means. With support from collagen,

1134:

enzyme, produces the final step in the collagen synthesis pathway. This enzyme acts on lysines and hydroxylysines producing aldehyde groups, which will eventually undergo covalent bonding between tropocollagen molecules. This polymer of tropocollagen is known as a collagen

3019:

tail tendon was modeled as being closest to the observed structure, although it oversimplified the topological progression of neighboring collagen molecules, and so did not predict the correct conformation of the discontinuous D-periodic pentameric arrangement termed

2990:

The molecular and packing structures of collagen eluded scientists over decades of research. The first evidence that it possesses a regular structure at the molecular level was presented in the mid-1930s. Research then concentrated on the conformation of the collagen

1057:: Once the final mRNA exits from the cell nucleus and enters into the cytoplasm, it links with the ribosomal subunits and the process of translation occurs. The early/first part of the new peptide is known as the signal sequence. The signal sequence on the 2564:

Collagen is known to be a viscoelastic solid. When the collagen fiber is modeled as two Kelvin-Voigt models in series, each consisting of a spring and a dashpot in parallel, the strain in the fiber can be modeled according to the following equation:

2335:, dominant autosomal disorder, results in weak bones and irregular connective tissue, some cases can be mild while others can be lethal. Mild cases have lowered levels of collagen type 1 while severe cases have structural defects in collagen. 1116:: Once outside the cell, membrane bound enzymes known as collagen peptidases, remove the "loose ends" of the procollagen molecule. What is left is known as tropocollagen. Defects in this step produce one of the many collagenopathies known as 1569:

Collagen-related diseases most commonly arise from genetic defects or nutritional deficiencies that affect the biosynthesis, assembly, posttranslational modification, secretion, or other processes involved in normal collagen production.

1003:

First, a three-dimensional stranded structure is assembled with amino acids glycine and proline as its principal components. This is not yet collagen but is its precursor: procollagen. Procollagen is then modified by the addition of

1475:

atom. For the same reason, the rings of the Pro and Hyp must point outward. These two amino acids help stabilize the triple helix – Hyp even more so than Pro; a lower concentration of them is required in animals such as fish, whose

2514:

parallel fibers, whereas skin consists of a net of wavy fibers, resulting in a much higher strength and lower ductility in tendon compared to skin. The mechanical properties of collagen at multiple hierarchical levels is given.

2692: 444:

integrity of the skeleton. The triple helical structure of collagen prevents it from being broken down by enzymes, it enables adhesiveness of cells and it is important for the proper assembly of the extracellular matrix.

1533:. However, advances in microscopy techniques (i.e. electron microscopy (EM) and atomic force microscopy (AFM)) and X-ray diffraction have enabled researchers to obtain increasingly detailed images of collagen structure 3126: 1504:

spaces of tissues. Additional assembly of fibrils is guided by fibroblasts, which deposit fully formed fibrils from fibripositors. In the fibrillar collagens, molecules are staggered to adjacent molecules by about

1411:. With type I collagen and possibly all fibrillar collagens, if not all collagens, each triple-helix associates into a right-handed super-super-coil referred to as the collagen microfibril. Each microfibril is 1075:

into the endoplasmic reticulum. Therefore, once the synthesis of new peptide is finished, it goes directly into the endoplasmic reticulum for post-translational processing. It is now known as preprocollagen.

2739:, such as by heating, the three tropocollagen strands separate partially or completely into globular domains, containing a different secondary structure to the normal collagen polyproline II (PPII) of 1467:

groups, along with the rich abundance of glycine, accounts for the tendency of the individual polypeptide strands to form left-handed helices spontaneously, without any intrachain hydrogen bonding.

256:. However, as of 2011, 28 types of human collagen have been identified, described, and divided into several groups according to the structure they form. All of the types contain at least one 4885:

Hamel BC, Pals G, Engels CH, van den Akker E, Boers GH, van Dongen PW, et al. (June 1998). "Ehlers-Danlos syndrome and type III collagen abnormalities: a variable clinical spectrum".

2950:

correction of wrinkles and skin aging. Collagen cremes are also widely sold even though collagen cannot penetrate the skin because its fibers are too large. Collagen is a vital protein in

2499:

scale, collagen has a lower modulus compared to the molecular scale, and varies depending on geometry, scale of observation, deformation state, and hydration level. By increasing the

419:

deposition within collagen occurs as a natural function of aging. Calcified points within collagen matrices show contrast in a moving display of blood and muscle, enabling methods of

1173:. These amino acids are found at specific locations relative to glycine and are modified post-translationally by different enzymes, both of which require vitamin C as a cofactor. 1415:

with its neighboring microfibrils to a degree that might suggest they are individually unstable, although within collagen fibrils, they are so well ordered as to be crystalline.

1541:

equal to the gap region) probably serve as nucleation sites for the deposition of long, hard, fine crystals of the mineral component, which is hydroxylapatite (approximately) Ca

5468: 654:-X and glycine-X-hydroxyproline, where X is any amino acid other than glycine, proline or hydroxyproline. The average amino acid composition for fish and mammal skin is given. 2848: 4569:

Minary-Jolandan M, Yu MF (September 2009). "Nanomechanical heterogeneity in the gap and overlap regions of type I collagen fibrils with implications for bone heterogeneity".

6304: 3118: 1430:

A distinctive feature of collagen is the regular arrangement of amino acids in each of the three chains of these collagen subunits. The sequence often follows the pattern

5352:

Gentleman E, Lay AN, Dickerson DA, Nauman EA, Livesay GA, Dee KC (September 2003). "Mechanical characterization of collagen fibers and scaffolds for tissue engineering".

5201:

Gentleman E, Lay AN, Dickerson DA, Nauman EA, Livesay GA, Dee KC (September 2003). "Mechanical characterization of collagen fibers and scaffolds for tissue engineering".

4466: 4131:

Houck JC, Sharma VK, Patel YM, Gladner JA (October 1968). "Induction of collagenolytic and proteolytic activities by anti-inflammatory drugs in the skin and fibroblast".

2995:, producing several competing models, although correctly dealing with the conformation of each individual peptide chain. The triple-helical "Madras" model, proposed by 559:. When collagen is made available to the wound bed, closure can occur. Wound deterioration, followed sometimes by procedures such as amputation, can thus be avoided. 5436: 1051:" prefix. The beginning of collagen synthesis begins with turning on genes associated with the formation of a particular alpha peptide (typically alpha 1, 2 or 3). 5088:

Gautieri A, Vesentini S, Redaelli A, Buehler MJ (February 2011). "Hierarchical structure and nanomechanics of collagen microfibrils from the atomistic scale up".

2506:

Limited tests have been done on the tensile strength of the collagen fiber, but generally it has been shown to have a lower Young's modulus compared to fibrils.

6668: 5041: 2325:

One thousand mutations have been identified in 12 out of more than 20 types of collagen. These mutations can lead to various diseases at the tissue level.

4676: 2570: 7091: 6116:

Okuyama K, Okuyama K, Arnott S, Takayanagi M, Kakudo M (October 1981). "Crystal and molecular structure of a collagen-like polypeptide (Pro-Pro-Gly)10".

1892: 90:. As the main component of connective tissue, it is the most abundant protein in mammals. 25% to 35% of a mammalian body's protein content is collagen. 5236:

Vesentini S, Fitié CF, Montevecchi FM, Redaelli A (June 2005). "Molecular assessment of the elastic properties of collagen-like homotrimer sequences".

1529:

was a barrier to the study of monomeric collagen until it was found that tropocollagen from young animals can be extracted because it is not yet fully

5812: 5446: 5387:

Puxkandl R, Zizak I, Paris O, Keckes J, Tesch W, Bernstorff S, et al. (February 2002). Bailey AJ, Macmillan J, Shrewry PR, Tatham AS (eds.).

160:, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in 6444:"Corneal collagen fibril structure in three dimensions: Structural insights into fibril assembly, mechanical properties, and tissue organization" 5314:

van der Rijt JA, van der Werf KO, Bennink ML, Dijkstra PJ, Feijen J (September 2006). "Micromechanical testing of individual collagen fibrils".

1095:

Glycosylation occurs by adding either glucose or galactose monomers onto the hydroxyl groups that were placed onto lysines, but not on prolines.

407:. Collagen is layered in variable densities with smooth muscle mass. The mass, distribution, age, and density of collagen all contribute to the 1525:

glycoproteins, and proteoglycans to form the different types of mature tissues from alternate combinations of the same key players. Collagen's

5131:

Pradhan SM, Katti DR, Katti KS (2011). "Steered Molecular Dynamics Study of Mechanical Response of Full Length and Short Collagen Molecules".

3789: 2456:

form. It may be one of the most abundant proteins in the fossil record, given that it appears to fossilize frequently, even in bones from the

4964: 3166: 5941: 5271:

Buehler MJ (August 2006). "Atomistic and continuum modeling of mechanical properties of collagen: Elasticity, fracture, and self-assembly".

5532: 4534:

Twardowski T, Fertala A, Orgel JP, San Antonio JD (2007). "Type I collagen and collagen mimetics as angiogenesis promoting superpolymers".

2770:

of horses and other animals to obtain glue. Collagen adhesive was used by Egyptians about 4,000 years ago, and Native Americans used it in

2400:

that supports most tissues and gives cells structure from the outside, but collagen is also found inside certain cells. Collagen has great

477:

and wounds. These collagens may be derived from bovine, equine, porcine, or even human sources; and are sometimes used in combination with

2805:

plastic adhesives, which are permanent. Animal sinews and skins, including leather, have been used to make useful articles for millennia.

6202:

Bella J, Eaton M, Brodsky B, Berman HM (October 1994). "Crystal and molecular structure of a collagen-like peptide at 1.9 A resolution".

5810:

Clark G, Parker E, Schaad J, Warren WJ (1935). "New measurements of previously unknown large interplanar spacings in natural materials".

411:

required to move blood back and forth. Individual cardiac valvular leaflets are folded into shape by specialized collagen under variable

7739: 1387:

A single collagen molecule, tropocollagen, is used to make up larger collagen aggregates, such as fibrils. It is approximately 300

590:: Collagen, in the presence of certain neutral salt molecules, can act as a nucleating agent causing formation of fibrillar structures. 3924: 146: 141: 7780: 6965: 6611:"On the packing structure of collagen: response 0to Okuyama et al.'s comment on Microfibrillar structure of type I collagen in situ" 5166:

Buehler MJ (January 2008). "Nanomechanics of collagen fibrils under varying cross-link densities: atomistic and continuum studies".

1866: 1374: 990: 542: 36:

Tropocollagen molecule: three left-handed procollagens (red, green, blue) join to form a right-handed triple helical tropocollagen.

4002:"Ascorbate requirement for hydroxylation and secretion of procollagen: relationship to inhibition of collagen synthesis in scurvy" 1485:

animals leads to their collagen having a lower thermal stability than mammalian collagen. This lower thermal stability means that

1451:

cross-links. This kind of regular repetition and high glycine content is found in only a few other fibrous proteins, such as silk

6661: 7785: 6982: 5741: 4427: 3040: 1972: 1674: 1646: 5682: 5626: 3079:"Mapping the ligand-binding sites and disease-associated mutations on the most abundant protein in the human, type I collagen" 378:

rings, is histologically, elastically and uniquely bound to cardiac muscle. The cardiac skeleton also includes the separating

7749: 7084: 4092:"Ascorbate is consumed stoichiometrically in the uncoupled reactions catalyzed by prolyl 4-hydroxylase and lysyl hydroxylase" 1356: 972: 524: 1047:: About 44 genes are associated with collagen formation, each coding for a specific mRNA sequence, and typically have the " 7471: 7375: 7350: 2492:

strengths than shorter ones due to short molecules having a large proportion of hydrogen bonds being broken and reformed.

2198: 5985:"Binding of phosphate and pyrophosphate ions at the active site of human angiogenin as revealed by X-ray crystallography" 4784: 1426:

coil to form tropocollagen. Many tropocollagens then bind together to form a fibril, and many of these then form a fibre.

7775: 7503: 7432: 7370: 7365: 4801:

Horton WA, Campbell D, Machado MA, Chou J (December 1989). "Type II collagen screening in the human chondrodysplasias".

3034: 1950: 1403:. These three left-handed helices are twisted together into a right-handed triple helix or "super helix", a cooperative 1262:

Triple alpha helical structure is formed inside the endoplasmic reticulum from two alpha-1 chains and one alpha-2 chain.

2909: 2856: 1139: 7421: 7380: 7267: 7262: 7257: 7251: 7170: 6930: 6842: 6654: 2801:

such as fine violins and guitars, which may have to be reopened for repairs – an application incompatible with tough,

2736: 1226: 1064: 331: 3551:

Drury JL, Mooney DJ (November 2003). "Hydrogels for tissue engineering: scaffold design variables and applications".

2881: 2348: 1802: 1702: 1642: 1117: 2751:. Besides food, gelatin has been used in pharmaceutical, cosmetic, and photography industries. It is also used as a 7459: 7395: 7338: 7310: 7300: 7230: 7163: 1744: 1706: 584:

properties: The large surface area available on collagen fibers can attract fibrogenic cells which help in healing.

5038: 3965:

Szpak P (2011). "Fish bone chemistry and ultrastructure: implications for taphonomy and stable isotope analysis".

2867: 2852: 1345: 961: 555:

Collagen is one of the body's key natural resources and a component of skin tissue that can benefit all stages of

513: 7448: 7183: 7145: 7077: 3045: 1773: 1352: 968: 520: 432: 2888: 7021: 6913: 4668: 4617:

Söderhäll C, Marenholz I, Kerscher T, Rüschendorf F, Esparza-Gordillo J, Worm M, et al. (September 2007).

1939: 404: 4485:"Candidate cell and matrix interaction domains on the collagen fibril, the predominant protein of vertebrates" 5058:

Zylberberg L, Laurin M (2011). "Analysis of fossil bone organic matrix by transmission electron microscopy".

1092:

hydroxylation of prolines and lysines causes a looser triple helix (which is formed by three alpha peptides).

225: 6957: 6922: 2786: 2484: 2328: 1856: 1638: 1497: 1250: 1025: 408: 387: 383: 6366:

Wess TJ, Hammersley AP, Wess L, Miller A (January 1998). "Molecular packing of type I collagen in tendon".

4369:"Collagen fibril architecture, domain organization, and triple-helical conformation govern its proteolysis" 5484:"Collagen Supplements for Aging and Wrinkles: A Paradigm Shift in the Fields of Dermatology and Cosmetics" 3227: 3011:. The microfibrillar structure of collagen fibrils in tendon, cornea and cartilage was imaged directly by 2895: 2720:

Collagen has a wide variety of applications, from food to medical. In the medical industry, it is used in

1222: 1170: 1160: 666: 2778:

as more than 8,000 years old, was found to be collagen – used as a protective lining on rope baskets and

7517: 3003:

in collagen. This model was supported by further studies of higher resolution in the late 20th century.

2712: 2503:

from zero to 3 per molecule, the maximum stress the fibril can support increases from 0.5 GPa to 6 GPa.

2473: 2100: 1285: 1068: 212: 7112: 6945: 6940: 6824: 6795: 6718: 6622: 6573: 6514: 6455: 6403:"Subfibrillar architecture and functional properties of collagen: a comparative study in rat tendons" 6258: 6211: 6160: 5898: 5847: 5776: 5563: 5280: 5097: 4993: 4380: 4325: 4267: 3974: 3437: 3386: 3374: 3000: 2877: 2397: 1404: 1245:

of lysine and proline amino acids occurs inside the lumen. This process is dependent on and consumes

1033: 83: 3232: 1516:

The D-period of collagen fibrils results in visible 67nm bands when observed by electron microscopy.

7344: 3813:"Type-1 pericytes accumulate after tissue injury and produce collagen in an organ-dependent manner" 3683:"Collagen dressing versus conventional dressings in burn and chronic wounds: a retrospective study" 3012: 2107: 1730: 1512: 1299:

which links hydroxylysine and lysine residues. Multiple collagen fibrils form into collagen fibers.

618: 400: 391: 173: 150: 4166: 3471:

Geiger M, Li RH, Friess W (November 2003). "Collagen sponges for bone regeneration with rhBMP-2".

1229:(RER). These peptide chains known as preprocollagen, have registration peptides on each end and a 1081:: Three modifications of the pre-pro-peptide occur leading to the formation of the alpha peptide: 7770: 7683: 7494: 6814: 6284: 6184: 6063: 5969: 5961: 5922: 5871: 4910: 4867: 4458: 4349: 3938: 3885: 3611: 3453: 3410: 3253: 2996: 2802: 2798: 2775: 2752: 2480: 2096: 1687: 1395:

strands (called alpha peptides, see step 2), each of which has the conformation of a left-handed

564: 5389:"Viscoelastic properties of collagen: synchrotron radiation investigations and structural model" 4483:

Sweeney SM, Orgel JP, Fertala A, McAuliffe JD, Turner KR, Di Lullo GA, et al. (July 2008).

3781: 3218:

Müller WE (February 2003). "The origin of metazoan complexity: porifera as integrated animals".

2488: 1690:

and is produced quickly by young fibroblasts before the tougher type I collagen is synthesized.

6560:

Okuyama K, Bächinger HP, Mizuno K, Boudko S, Engel J, Berisio R, et al. (September 2009).

6331:

Fraser RD, MacRae TP, Miller A (January 1987). "Molecular packing in type I collagen fibrils".

5767:

Wyckoff RW, Corey RB, Biscoe J (August 1935). "X-Ray Reflections of Long Spacing from Tendon".

3629:

Oliveira SM, Ringshia RA, Legeros RZ, Clark E, Yost MJ, Terracio L, et al. (August 2010).

1185:

derived from lysine – depending on the type of collagen, varying numbers of hydroxylysines are

7688: 7498: 7289: 7036: 7013: 6677: 6591: 6542: 6483: 6424: 6383: 6348: 6276: 6247:"Crystalline three-dimensional packing is a general characteristic of type I collagen fibrils" 6227: 6176: 6133: 6098: 6055: 6014: 5914: 5863: 5792: 5690: 5663: 5599: 5581: 5513: 5462: 5418: 5369: 5331: 5296: 5253: 5218: 5183: 5148: 5113: 5021: 4960: 4937: 4936:. Vol. Collagen IV-Related Nephropathies. Seattle WA: University of Washington, Seattle. 4902: 4859: 4818: 4776: 4732: 4650: 4586: 4551: 4516: 4450: 4408: 4341: 4295: 4231: 4201: 4148: 4113: 4072: 4023: 3930: 3920: 3844: 3763: 3714: 3660: 3603: 3568: 3533: 3488: 3402: 3355: 3314: 3245: 3162: 3100: 2975: 2793:. Collagen normally converts to gelatin, but survived due to dry conditions. Animal glues are 2445: 2364: 1841: 1681: 1659: 1072: 1037: 482: 345: 279: 157: 107: 87: 4619:"Variants in a novel epidermal collagen gene (COL29A1) are associated with atopic dermatitis" 3903:

Brodsky B, Persikov AV (1 January 2005). "Molecular structure of the collagen triple helix".

7613: 7608: 7569: 7564: 7559: 7554: 7549: 7294: 7158: 6806: 6630: 6581: 6532: 6522: 6473: 6463: 6414: 6375: 6340: 6313: 6266: 6219: 6168: 6125: 6090: 6081:

Fraser RD, MacRae TP, Suzuki E (April 1979). "Chain conformation in the collagen molecule".

6045: 6004: 5996: 5953: 5906: 5855: 5820: 5784: 5653: 5589: 5571: 5503: 5495: 5408: 5400: 5361: 5323: 5288: 5245: 5210: 5175: 5140: 5105: 5067: 5011: 5001: 4894: 4849: 4836:

Malfait F, Francomano C, Byers P, Belmont J, Berglund B, Black J, et al. (March 2017).

4810: 4766: 4722: 4714: 4640: 4630: 4578: 4543: 4506: 4496: 4442: 4398: 4388: 4333: 4285: 4275: 4193: 4140: 4103: 4062: 4054: 4013: 3982: 3912: 3875: 3834: 3824: 3753: 3745: 3734:"Topical Collagen-Based Biomaterials for Chronic Wounds: Rationale and Clinical Application" 3704: 3694: 3650: 3642: 3595: 3560: 3523: 3515: 3480: 3445: 3394: 3345: 3304: 3296: 3270:

Sabiston textbook of surgery board review, 7th edition. Chapter 5 wound healing, question 14

3237: 3191: 3090: 2729: 2487:

simulations, as well as numerous experimental methods, have led to several estimates of the

2401: 2385: 2338: 1852: 1837: 1713: 1654: 1597: 1558: 1477: 1418: 1239:

Signal peptides are cleaved inside the RER and the chains are now known as pro-alpha chains.

1203: 1131: 431:). Pathology of the collagen underpinning of the heart is understood within the category of 371: 341: 321: 46: 5144: 4701:

Mahajan VB, Olney AH, Garrett P, Chary A, Dragan E, Lerner G, et al. (November 2010).

273:(Fibril Associated Collagens with Interrupted Triple Helices) (Type IX, XII, XIV, XIX, XXI) 7734: 7591: 7586: 7581: 7177: 7139: 6837: 5045: 2748: 2721: 2381: 2358: 1833: 1769: 1691: 1663: 1605: 1493: 1269: 1214:

Most collagen forms in a similar manner, but the following process is typical for type I:

1105: 575: 470: 420: 395: 350: 335: 307: 253: 189: 5715: 4184:

Hulmes DJ (2002). "Building collagen molecules, fibrils, and suprafibrillar structures".

3811:

Birbrair A, Zhang T, Files DC, Mannava S, Smith T, Wang ZM, et al. (November 2014).

3428:

Cunniffe G, O'Brien F (2011). "Collagen scaffolds for orthopedic regenerative medicine".

2313:

In addition to the above-mentioned disorders, excessive deposition of collagen occurs in

6626: 6577: 6518: 6459: 6302:

Fraser RD, MacRae TP (1981). "Unit cell and molecular connectivity in tendon collagen".

6262: 6215: 6164: 5902: 5851: 5780: 5594: 5567: 5551: 5393:

Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences

5284: 5101: 4997: 4428:"Role of X-ray Scattering Techniques in Understanding the Collagen Structure of Leather" 4384: 4329: 4271: 3978: 3441: 3390: 570:

Throughout the four phases of wound healing, collagen performs the following functions:

7221: 6935: 6768: 6743: 6537: 6502: 6419: 6402: 6009: 5984: 5508: 5483: 5413: 5388: 5016: 4981: 4898: 4727: 4702: 4645: 4618: 4511: 4484: 4403: 4368: 4290: 4255: 4067: 4042: 3839: 3812: 3758: 3733: 3709: 3682: 3655: 3630: 3309: 3284: 2962:, and other tissues. Its production decreases with age and factors like sun damage and 2183: 2165: 2131: 2068: 2033: 1982: 1902: 1482: 1439: 1292: 1230: 1176: 718: 643: 630: 626: 610: 428: 291:

MACIT (Membrane Associated Collagens with Interrupted Triple Helices) (Type XIII, XVII)

270: 103: 5552:"Collagen supplementation in skin and orthopedic diseases: A review of the literature" 5365: 5214: 4108: 4091: 3916: 3564: 2902: 1489:

derived from fish collagen is not suitable for many food and industrial applications.

1412: 188:. Collagen constitutes 1% to 2% of muscle tissue and accounts for 6% of the weight to 7764: 7522: 7104: 6849: 6478: 6443: 6344: 6317: 6271: 6246: 6129: 6094: 5965: 5658: 5641: 5441: 4462: 4316:

Hulmes DJ, Miller A (1979). "Quasi-hexagonal molecular packing in collagen fibrils".

4144: 3615: 3457: 3414: 3056: 2943: 2794: 2725: 2083: 1521: 1501: 1408: 1296: 1256: 1246: 1242: 1186: 1182: 1144: 1127: 1013: 861: 835: 757: 731: 556: 486: 474: 424: 379: 181: 169: 6288: 6151:

Traub W, Yonath A, Segal DM (March 1969). "On the molecular structure of collagen".

5875: 4914: 3942: 3889: 3257: 2687:{\displaystyle {\frac {d\epsilon _{D}}{d\epsilon _{T}}}=\alpha +(\beta -\alpha )exp} 1291:

Multiple tropocollagen molecules form collagen fibrils, via covalent cross-linking (

1028:, a long-term deficiency in this vitamin results in impaired collagen synthesis and 7646: 6188: 6067: 5926: 5618: 4871: 4752:"Mutations in type I collagen genes resulting in osteogenesis imperfecta in humans" 4353: 2813: 2771: 2441: 2432:, it is responsible for skin strength and elasticity, and its degradation leads to 1935: 1718: 1626:

surrounding muscle fibers, fibrocartilage, and the organic part of bones and teeth.

1302:

Collagen may be attached to cell membranes via several types of protein, including

1190: 614: 257: 165: 95: 32: 5576: 3586:

Tonndorf R, Aibibu D, Cherif C (January 2020). "Collagen multifilament spinning".

3398: 3375:"Materials science perspective of multifunctional materials derived from collagen" 1169:

Collagen contains two unusual derivative amino acids not directly inserted during

1084:

The signal peptide on the N-terminal is removed, and the molecule is now known as

17: 4982:"Nature designs tough collagen: explaining the nanostructure of collagen fibrils" 4635: 4222:

Hulmes DJ (1992). "The collagen superfamily--diverse structures and assemblies".

3015:

in the late 20th century and early 21st century. The microfibrillar structure of

578:

serve to guide fibroblasts. Fibroblasts migrate along a connective tissue matrix.

7724: 7653: 7389: 7334: 6997: 6748: 6691: 5983:

Leonidas DD, Chavali GB, Jardine AM, Li S, Shapiro R, Acharya KR (August 2001).

5788: 5179: 4703:"Collagen XVIII mutation in Knobloch syndrome with acute lymphoblastic leukemia" 3334:"Collagenous transmembrane proteins: recent insights into biology and pathology" 3300: 3077:

Di Lullo GA, Sweeney SM, Korkko J, Ala-Kokko L, San Antonio JD (February 2002).

3008: 2790: 2763: 2740: 2314: 2006: 1877: 1726: 1423: 1400: 1392: 1334: 1303: 1265: 1017: 950: 581: 502: 454: 375: 285: 6507: