2.A.23.1.5
Archaeal aspartate transporter, Gltph (GltPh) (3-D structure known; 3V8F and 3V8G) (Boudker et al., 2007; Yernool et al., 2004). Cotransports aspartate with 2 Na+ (Ryan et al., 2009) or 3 Na+ (Groeneveld and Slotboom, 2010) or 1Na+ plus 1 H+ plus 1 K+ (Machtens et al. 2015). Reyes et al. (2009) have solved the structure of the inward facing state by cysteine crosslinking. The loop between TMSs 3 and 4 plays an essential role in transport (Compton et al., 2010). Gltph shows opposite movement of the external gate upon binding cotransported sodium compared with substrate (Focke et al., 2011). The transport pathway and the conformational changes involved have been suggested based on modeling studies (Stolzenberg et al. 2012; Wang et al. 2018). Individual transport domains may alternate between periods of quiescence and
periods of rapid transitions. The switch to the dynamic mode may be due to separation of the transport domain from the trimeric scaffold which precedes domain
movements across the bilayer (Akyuz et al. 2013). This spontaneous dislodging of the substrate-loaded transport domain
is approximately 100-fold slower than subsequent transmembrane movements and may be rate determining
in the transport cycle. Interactions between the transporter and specific lipids in artificial membranes have revealed effects on activity, and mechanisms have been proposed (McIlwain et al. 2015). The system can also function as an anion channel (Machtens et al. 2015). Millisecond dynamics have been described (Matin et al. 2020).
|
Accession Number: | O59010 |
Protein Name: | Proton glutamate symport protein |
Length: | 425 |
Molecular Weight: | 44807.00 |
Species: | Pyrococcus horikoshii [53953] |
Number of TMSs: | 9 |
Location1 / Topology2 / Orientation3: |
Cell membrane1 / Multi-pass membrane protein2 |
Substrate |
anion, glutamate(2-), aspartate(2-) |
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1: MGLYRKYIEY PVLQKILIGL ILGAIVGLIL GHYGYADAVK TYVKPFGDLF VRLLKMLVMP
61: IVFASLVVGA ASISPARLGR VGVKIVVYYL LTSAFAVTLG IIMARLFNPG AGIHLAVGGQ
121: QFQPKQAPPL VKILLDIVPT NPFGALANGQ VLPTIFFAII LGIAITYLMN SENEKVRKSA
181: ETLLDAINGL AEAMYKIVNG VMQYAPIGVF ALIAYVMAEQ GVKVVGELAK VTAAVYVGLT
241: LQILLVYFVL LKIYGIDPIS FIKKAKDAML TAFVTRSSSG TLPVTMRVAK EMGISEGIYS
301: FTLPLGATIN MDGTALYQGV CTFFIANALG SHLTVGQQLT IVLTAVLASI GTAGVPGAGA
361: IMLAMVLESV GLPLTDPNVA AAYAMILGID AILDMGRTMV NVTGDLTGTA IVAKTEGELE
421: KGVIA