TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*4.A.7.1.1









The L-ascorbate transporting and phosphorylating group translocator, SgaTBA or UlaCBA (SgaT = UlaA = YjfS; SgaB = UlaB = YjfT; SgaA = UlaC = PtxA = YjfU) (Hvorup et al., 2003; Zhang et al., 2003). Two conformations of the 3-d structure have been determined at 1.65 and 2.35 Å resolution, respectively (Luo et al., 2015). UlaA (SgaT) forms a homodimer with a novel fold. Each UlaA protomer consists of 11 TMSs arranged into a 'V-motif' domain and a 'core' domain. The V motifs form the interface between the two protomers, and the core-domain residues coordinate vitamin C. Alternating access of the substrate to the two sides of the cell membrane may be achieved through rigid-body rotation of the core relative to the V motif (Luo et al., 2015; Zhang et al., 2003). This structure does not resemble the ChbC structure (TC# 4.A.3.2.8).

Bacteria
Proteobacteria
L-ascorbate (L-Asc) IIC-IIB-IIA complex of E. coli
IIC (SgaT)
IIB (SgaB)
IIA (SgaA)
*4.A.7.1.2









Virulence-associate PTS, VpeABC (substrate unknown).  Essential for virulence and normal colonization of the kidney and intestine by uropathogneic E. coli (UPEC) (Martinez-Jéhanne et al. 2012).

Bacteria
Proteobacteria
VpeABC of E. coli AL511
*4.A.7.1.3









Putative Enzyme IIC specific for ascorbate of 410 aas

Bacteria
Firmicutes
IICasc of Clostridium carboxidivorans
*4.A.7.1.4









Uncharacterized protein of 420 aas; possibly a IIC or IICB PTS protein (based on homology); SgaT/UlaA

Bacteria
Proteobacteria
UlaA/SgaT of Klebsiella pneumoniae
*4.A.7.1.5









Uncharacterized protein of 424 aas and 12 TMSs

Bacteria
Firmicutes
UP of Turicibacter sanguinis
*4.A.7.1.6









The PTS ascorbate transporter subunits IIBC (596 aas and 11 TMSs) and IIA (155 aas).The 3-d structure has been determined at high resolution of the inward open configuration, showing that ascorbate translocation can be achieved by a rigid-body movement of the substrate-binding core domain relative to the V motif domain, which brings along the transmembrane helices TM2 and TM7 of the V motif domain to undergo a winding at the pivotal positions (Luo et al. 2018). This completes the picture of the transport cycle of the ascorbate superfamily of membrane-spanning EIIC components of the PTS.

Bacteria
Proteobacteria
Ascorbate transporter of Pasteurella multocida