Structural highlights
FunctionULAA_ECOLI The phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS), a major carbohydrate active-transport system, catalyzes the phosphorylation of incoming sugar substrates concomitant with their translocation across the cell membrane. This system is involved in ascorbate transport. Publication Abstract from PubMedBacteria use vitamin C (L-ascorbic acid) as a carbon source under anaerobic conditions. The phosphoenolpyruvate-dependent phosphotransferase system (PTS), comprising a transporter (UlaA), a IIB-like enzyme (UlaB) and a IIA-like enzyme (UlaC), is required for the anaerobic uptake of vitamin C and its phosphorylation to L-ascorbate 6-phosphate. Here, we present the crystal structures of vitamin C-bound UlaA from Escherichia coli in two conformations at 1.65-A and 2.35-A resolution. UlaA forms a homodimer and exhibits a new fold. Each UlaA protomer consists of 11 transmembrane segments 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. The alternating access of the substrate from the opposite side of the cell membrane may be achieved through rigid-body rotation of the core relative to the V motif. Crystal structure of a phosphorylation-coupled vitamin C transporter.,Luo P, Yu X, Wang W, Fan S, Li X, Wang J Nat Struct Mol Biol. 2015 Feb 16. doi: 10.1038/nsmb.2975. PMID:25686089[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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