2.A.15.1.10
Glycine betaine transporter, BetP. BetP is a transporter with three different functions: betaine transport, osmosensing, and osmoregulation (Krämer and Morbach 2004). The x-ray structure is known (3PO3; 2WIT; Ressl et al., 2009). Regulatory crosstalk in the trimeric BetP has been reported (Gärtner et al., 2011). An extracellular K+ -dependent interaction site modulates betaine-binding (Ge et al., 2011). The porter is trimeric and exhibits structural asymmetry (Tsai et al., 2011). The C-terminal domain is involved in osmosensing and is trimeric like wild-type BetP. The two Na+ binding sites are between TMSs 1 and 8 in the first and second 5 TMS repeats, and between the equivalent TMSs 6 and 3 in the second and first repeats, respectively (Khafizov et al. 2012). interdependent binding of betaine and two sodium ions is observed during the coupling
process. All three sites undergo progressive reshaping and dehydration
during the alternating-access cycle, with the most optimal coordination
of all substrates found in the closed state (Perez et al. 2014). BetP is active and regulated only when negatively charged lipids such as phosphatidyl glycerol are present, and the mechanism has been discussed (Güler et al. 2016). The K+-sensing
C-terminal domain results in K+-dependent cooperative betaine-binding (Ge et al. 2011). BetP is a homotrimer lacking exact 3-fold symmetry. The observed differences may be due to crystal packing, or they may reflect different functional states of the transporter, related to osmosensing and osmoregulation (Ziegler et al. 2004). The projection map of BetP showed no clear resemblance to other secondary transporters of known structure in 2004.
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Accession Number: | P54582 |
Protein Name: | Glycine betaine transporter BetP |
Length: | 595 |
Molecular Weight: | 64209.00 |
Species: | Corynebacterium glutamicum [1718] |
Number of TMSs: | 12 |
Location1 / Topology2 / Orientation3: |
Cell membrane1 / Multi-pass membrane protein2 |
Substrate |
potassium(1+), glycine betaine |
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Entrez Gene ID: |
1018885
3342778
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Pfam: |
PF02028
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KEGG: |
cgb:cg1016
cgl:NCgl0856
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[1] “The complete Corynebacterium glutamicum ATCC 13032 genome sequence and its impact on the production of L-aspartate-derived amino acids and vitamins.” Kalinowski J. et.al. 12948626
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1: MTTSDPNPKP IVEDAQPEQI TATEELAGLL ENPTNLEGKL ADAEEEIILE GEDTQASLNW
61: SVIVPALVIV LATVVWGIGF KDSFTNFASS ALSAVVDNLG WAFILFGTVF VFFIVVIAAS
121: KFGTIRLGRI DEAPEFRTVS WISMMFAAGM GIGLMFYGTT EPLTFYRNGV PGHDEHNVGV
181: AMSTTMFHWT LHPWAIYAIV GLAIAYSTFR VGRKQLLSSA FVPLIGEKGA EGWLGKLIDI
241: LAIIATVFGT ACSLGLGALQ IGAGLSAANI IEDPSDWTIV GIVSVLTLAF IFSAISGVGK
301: GIQYLSNANM VLAALLAIFV FVVGPTVSIL NLLPGSIGNY LSNFFQMAGR TAMSADGTAG
361: EWLGSWTIFY WAWWISWSPF VGMFLARISR GRSIREFILG VLLVPAGVST VWFSIFGGTA
421: IVFEQNGESI WGDGAAEEQL FGLLHALPGG QIMGIIAMIL LGTFFITSAD SASTVMGTMS
481: QHGQLEANKW VTAAWGVATA AIGLTLLLSG GDNALSNLQN VTIVAATPFL FVVIGLMFAL
541: VKDLSNDVIY LEYREQQRFN ARLARERRVH NEHRKRELAA KRRRERKASG AGKRR