TCID | Name | Domain | Kingdom/Phylum | Protein(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 |
Pseudomonadota | 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 |
Pseudomonadota | VpeABC of E. coli AL511 |
4.A.7.1.3 | Putative Enzyme IIC specific for ascorbate of 410 aas | Bacteria |
Bacillota | 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 |
Pseudomonadota | UlaA/SgaT of Klebsiella pneumoniae |
4.A.7.1.5 | Uncharacterized protein of 424 aas and 12 TMSs | Bacteria |
Bacillota | 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 |
Pseudomonadota | Ascorbate transporter of Pasteurella multocida |