Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
membrane | peripheral membrane protein | Escherichia coli | 16020 | - |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | Escherichia coli | enzyme WbdD is also active as polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol kinase, EC 2.7.1.181 | ? | - |
? | |
S-adenosyl-L-methionine + O9a antigenic polysaccharide | Escherichia coli | - |
S-adenosyl-L-homocysteine + methylated O9a antigenic polysaccharide | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | enzyme WbdD is also active as polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol kinase, EC 2.7.1.181 | Escherichia coli | ? | - |
? | |
S-adenosyl-L-methionine + O9a antigenic polysaccharide | - |
Escherichia coli | S-adenosyl-L-homocysteine + methylated O9a antigenic polysaccharide | - |
? |
Synonyms | Comment | Organism |
---|---|---|
chain-terminating dual kinase/methyltransferase | - |
Escherichia coli |
WbdD | - |
Escherichia coli |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
S-adenosyl-L-methionine | - |
Escherichia coli |
General Information | Comment | Organism |
---|---|---|
physiological function | In Escherichia coli O9a, the peripheral membrane protein WbdD terminates polymerization by adding a methyl phosphate to the non-reducing end of the nascent O9a polymer. The O9a system is a representative of the widespread ATP-binding cassette transporter-dependent assembly pathway. This terminal modification is required for recognition and export of the completed O-PS across the cytoplasmic membrane by its cognate ATP-binding cassette transporter. The recognition event is mediated by the nucleotide-binding domain polypeptide of the transporter, which possesses a serotype-specific carbohydrate-binding module that only binds terminated O-PS chains. The WbdD terminator plays an additional pivotal structural role in recruiting WbdA to the membrane. The stoichiometry of WbdA:WbdD in active complexes is a critical factor in establishing the chain length distribution of the resulting glycans. The size of the O9a polysaccharide is determined by the chain-terminating dual kinase/methyltransferase (WbdD) that is tethered to the membrane and recruits polymerase/glycosyltransferase WbdA into an active enzyme complex by protein-protein interactions. Identification via bacterial two-hybrid analysis of a surface-exposed alpha-helix in the C-terminal mannosyltransferase domain of WbdA as the site of interaction with WbdD, the C-terminal domain was unable to interact with WbdD in the absence of its N-terminal partner. The WbdD protein orchestrates critical localization and coordination of activities involved in chain extension and termination. Complex domain interactions are needed to position the polymerase components appropriately for assembly into a functional complex located at the cytoplasmic membrane. WbdD is therefore a central player in a sophisticated quality control system that dictates the distribution of chain lengths and marks those chains with a terminal export tag | Escherichia coli |