246:
NADH/NAD may control gating. Multiple crystal structures of two KTN domains complexed with NAD or NADH reveal that these ligands control the oligomeric (tetrameric) state of KTN. The results suggest that KTN is inherently flexible, undergoing a large conformational change through a hinge motion. The KTN domains of Kef channels interact dynamically with the transporter. The KTN conformation then controls permease activity.
249:
Both yeast transport systems are believed to function by K:H symport, but the wheat protein functions by K:Na symport. It is possible that some of these proteins can function by a channel-type mechanism. Positively charged residues in TMS8 of several ktr/Trk/HKT transporters probably face the channel
245:
Trk family members regulate various K transporters in all three domains of life. These regulatory subunits are generally called K transport/nucleotide binding subunits. TrkA domains can bind NAD and NADH, possibly allowing K transporters to be responsive to the redox state of the cell. The ratio of
275:
Saier MH, Eng BH, Fard S, Garg J, Haggerty DA, Hutchinson WJ, Jack DL, Lai EC, Liu HJ, Nusinew DP, Omar AM, Pao SS, Paulsen IT, Quan JA, Sliwinski M, Tseng TT, Wachi S, Young GB (February 1999). "Phylogenetic characterization of novel transport protein families revealed by genome analyses".
219:
protein is 533 residues, and the yeast proteins vary between 841 and 1241 residues. These proteins possess 8 putative transmembrane α-helical spanners (TMSs). An 8 TMS topology with N- and C-termini on the inside, has been established for AtHKT1 of
638:
406:"Evidence in support of a four transmembrane-pore-transmembrane topology model for the Arabidopsis thaliana Na+/K+ translocating AtHKT1 protein, a member of the superfamily of K+ transporters"
203:
possesses at least two paralogues, high- and low-affinity K transporters. Folding pattern seen in Trk proteins resembles quadruplicated primitive K channels of the VIC superfamily (
642:
132:
88:
76:
316:"Na+-dependent K+ uptake Ktr system from the cyanobacterium Synechocystis sp. PCC 6803 and its role in the early phases of cell adaptation to hyperosmotic shock"
358:
Yu FH, Yarov-Yarovoy V, Gutman GA, Catterall WA (December 2005). "Overview of molecular relationships in the voltage-gated ion channel superfamily".
683:
673:
215:
The sizes of the Trk family members vary from 423 residues to 1235 residues. The bacterial proteins are of 423-558 residues, the
668:
152:
465:"Epitope tagging of the yeast K(+) carrier Trk2p demonstrates folding that is consistent with a channel-like structure"
678:
237:) instead of typical 12 TMS carriers. As homology has been established between Trk carriers and VIC family channels.
250:
and block a conformational change that is essential for channel activity while allowing secondary active transport.
663:
207:) instead of typical 12 TMS carriers. Homology has been established between Trk carriers and VIC family channels.
658:
172:
229:
140:
183:
The phylogenetic tree reveals that the proteins cluster according to phylogeny of the source organism with
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The proteins of the Trk family are derived from Gram-negative and Gram-positive bacteria, yeast and plants.
582:"A mechanism of regulating transmembrane potassium flux through a ligand-mediated conformational switch"
314:
Matsuda N, Kobayashi H, Katoh H, Ogawa T, Futatsugi L, Nakamura T, Bakker EP, Uozumi N (December 2004).
136:
417:
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Kato Y, Sakaguchi M, Mori Y, Saito K, Nakamura T, Bakker EP, Sato Y, Goshima S, Uozumi N (May 2001).
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127:
233:. This folding pattern resembles quadruplicated primitive K channels of the VIC superfamily (
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The putative generalized transport reaction catalyzed by the Trk family members is:
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93:
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57:
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Bateman A, Birney E, Durbin R, Eddy SR, Howe KL, Sonnhammer EL (January 2000).
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Proceedings of the
National Academy of Sciences of the United States of America
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Biochimica et
Biophysica Acta (BBA) - Reviews on Biomembranes
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Creative
Commons Attribution-ShareAlike 3.0 Unported License
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the Gram-negative and Gram-positive bacterial Ktr proteins,
637:, which is licensed in a way that permits reuse under the
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the plant proteins comprising four distinct clusters.
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Roosild TP, Miller S, Booth IR, Choe S (June 2002).
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463:Zeng GF, Pypaert M, Slayman CL (January 2004).
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173:voltage-gated ion channel (VIC) superfamily.
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187:the Gram-negative bacterial Trk proteins,
634:"2.A.38 The K+ Transporter (Trk) Family"
505:"2.A.38 The K+ Transporter (Trk) Family"
267:
645:. All relevant terms must be followed.
18:
7:
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530:"The Pfam protein families database"
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257:K (out) + H (out) ⇌ K (in) + H (in).
469:The Journal of Biological Chemistry
320:The Journal of Biological Chemistry
14:
631:, this article uses content from
22:Potassium transporter TrkH/TrkA
1:
599:10.1016/s0092-8674(02)00768-7
290:10.1016/s0304-4157(98)00023-9
104:Available protein structures:
16:Family of transport proteins
700:
684:Integral membrane proteins
674:Transmembrane transporters
99:
169:Transporter (Trk) Family
360:Pharmacological Reviews
669:Transmembrane proteins
534:Nucleic Acids Research
482:10.1074/jbc.M309760200
431:10.1073/pnas.101556598
333:10.1074/jbc.M407268200
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193:the yeast proteins and
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641:, but not under the
546:10.1093/nar/28.1.263
422:2001PNAS...98.6488K
171:is a member of the
679:Transport proteins
372:10.1124/pr.57.4.13
664:Membrane proteins
217:Triticum aestivum
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153:structure summary
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512:. Retrieved
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284:(1): 1–56.
223:A. thaliana
89:OPM protein
27:Identifiers
653:Categories
514:2016-04-16
262:References
116:structures
629:this edit
235:TC #1.A.1
211:Structure
205:TC #1.A.1
58:IPR003445
608:12086676
564:10592242
491:14570869
450:11344270
380:16382097
342:15459199
298:10082980
241:Function
179:Homology
133:RCSB PDB
53:InterPro
616:9265433
418:Bibcode
388:2643413
46:PF02386
627:As of
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555:102420
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148:PDBsum
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70:2.A.38
32:Symbol
612:S2CID
441:33495
384:S2CID
643:GFDL
604:PMID
586:Cell
560:PMID
509:TCDB
487:PMID
446:PMID
376:PMID
338:PMID
294:PMID
282:1422
164:The
141:PDBj
137:PDBe
120:ECOD
110:Pfam
94:4j7c
65:TCDB
41:Pfam
594:doi
590:109
550:PMC
542:doi
477:doi
473:279
436:PMC
426:doi
368:doi
328:doi
324:279
286:doi
128:PDB
35:Trk
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166:K
82:8
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.