earticle

영어

O-antigen of Vibrio cholerae O1 is controlled by ABC transporter-dependent pathway. O-antigen synthesis controlled by this pathway is initiated by a homolog of WecA, which catalyzes the transfer of GlcNAc-1-P from UDP-GlcNAc (donor) to undecaprenyl phosphate (acceptor). However, it speculates that an initial O-antigen synthesis of V. cholerae O1 is regulated by a homolog of WbaP (undecaprenyl phosphate galactose-1-phosphate tranferase). In this work, we characterized new glycosyltransferase WbeW from V. cholerae O1. Sequence and topology analyses of WbeW revealed that the protein might be a member of polyisoprenyl phosphate hexose-1-phosphate tranferase (PHPT) family. Through studies of subcellular location of His6-WbeW protein and its derivatives, which deleted with several amino acids from N-terminus, we found that the His6-WbeW protein was associated to membrane and its membrane association might be affected by diverse factors as well as α-helix transmembrane domain. The activity assay showed that the protein catalyzes the transfer of galactose-1-phosphate from UDP-Gal to undecaprenyl phosphate. This is the first report that an initial glycan of O-antigen formed by ABC-transporter-dependent pathway is galactose but not N-acetylglucosamine. This indicates that there might be a new mechanism of ABC-transporter-dependent pathway-controlled O-antigen synthesis.