UniProt functional annotation for Q93S40



	UniProt functional annotation for Q93S40

UniProt code: Q93S40.

Organism: Neisseria meningitidis.

Taxonomy: Bacteria; Proteobacteria; Betaproteobacteria; Neisseriales; Neisseriaceae; Neisseria.

Function: Catalyzes the O-acetylation of capsular polymeric sialic acid consisting of polymers of (2->6)-alpha-D-glucosyl-(1->4)-N-acetyl- alpha-D-neuraminosyl residues. Shows high substrate specificity toward polymers of sialic acid that contains a large number of residues. {ECO:0000269|PubMed:19525232}.

Catalytic activity: Reaction=[(2->6)-alpha-D-glucosyl-(1->4)-N-acetyl-alpha-D- neuraminosyl](n) + n acetyl-CoA = [(2->6)-alpha-D-glucosyl-(1->4)- N,7-O-diacetyl-alpha-D-neuraminosyl](n) + n CoA; Xref=Rhea:RHEA:55848, Rhea:RHEA-COMP:14318, Rhea:RHEA-COMP:14319, ChEBI:CHEBI:57287, ChEBI:CHEBI:57288, ChEBI:CHEBI:139287, ChEBI:CHEBI:139288; Evidence={ECO:0000269|PubMed:19525232};

Catalytic activity: Reaction=[(2->6)-alpha-D-glucosyl-(1->4)-N-acetyl-alpha-D- neuraminosyl](n) + n acetyl-CoA = [(2->6)-alpha-D-glucosyl-(1->4)- N,O(9)-diacetyl-alpha-D-neuraminosyl](n) + n CoA; Xref=Rhea:RHEA:55852, Rhea:RHEA-COMP:14318, Rhea:RHEA-COMP:14320, ChEBI:CHEBI:57287, ChEBI:CHEBI:57288, ChEBI:CHEBI:139287, ChEBI:CHEBI:139289; Evidence={ECO:0000269|PubMed:19525232};

Biophysicochemical properties: Kinetic parameters: KM=210 uM for acetyl-CoA {ECO:0000269|PubMed:19525232}; KM=18.5 uM for polymer of sialic acid {ECO:0000269|PubMed:19525232}; Note=kcat is 1.3 sec(-1) with acetyl-CoA as substrate. kcat is 2.1 sec(-1) with polymer of sialic acid as substrate. {ECO:0000269|PubMed:19525232};

Subunit: Homotrimer. {ECO:0000269|PubMed:19525232}.

Miscellaneous: Polymeric sialic acid-containing capsule provides a means for the bacteria to evade the immune response during infection by mimicking host sialic acid-containing cell surface structures. O- acetylation of the sialic acid residues of capsular polysaccharides alters their immunogenicity and susceptibility to glycosidases. {ECO:0000303|PubMed:19525232}.

Similarity: Belongs to the transferase hexapeptide repeat family. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.


Organism:		Neisseria meningitidis.
Taxonomy:		Bacteria; Proteobacteria; Betaproteobacteria; Neisseriales; Neisseriaceae; Neisseria.



Function:		Catalyzes the O-acetylation of capsular polymeric sialic acid consisting of polymers of (2->6)-alpha-D-glucosyl-(1->4)-N-acetyl- alpha-D-neuraminosyl residues. Shows high substrate specificity toward polymers of sialic acid that contains a large number of residues. {ECO:0000269\|PubMed:19525232}.


Catalytic activity:		Reaction=[(2->6)-alpha-D-glucosyl-(1->4)-N-acetyl-alpha-D- neuraminosyl](n) + n acetyl-CoA = [(2->6)-alpha-D-glucosyl-(1->4)- N,7-O-diacetyl-alpha-D-neuraminosyl](n) + n CoA; Xref=Rhea:RHEA:55848, Rhea:RHEA-COMP:14318, Rhea:RHEA-COMP:14319, ChEBI:CHEBI:57287, ChEBI:CHEBI:57288, ChEBI:CHEBI:139287, ChEBI:CHEBI:139288; Evidence={ECO:0000269\|PubMed:19525232};
Catalytic activity:		Reaction=[(2->6)-alpha-D-glucosyl-(1->4)-N-acetyl-alpha-D- neuraminosyl](n) + n acetyl-CoA = [(2->6)-alpha-D-glucosyl-(1->4)- N,O(9)-diacetyl-alpha-D-neuraminosyl](n) + n CoA; Xref=Rhea:RHEA:55852, Rhea:RHEA-COMP:14318, Rhea:RHEA-COMP:14320, ChEBI:CHEBI:57287, ChEBI:CHEBI:57288, ChEBI:CHEBI:139287, ChEBI:CHEBI:139289; Evidence={ECO:0000269\|PubMed:19525232};
Biophysicochemical properties:		Kinetic parameters: KM=210 uM for acetyl-CoA {ECO:0000269\|PubMed:19525232}; KM=18.5 uM for polymer of sialic acid {ECO:0000269\|PubMed:19525232}; Note=kcat is 1.3 sec(-1) with acetyl-CoA as substrate. kcat is 2.1 sec(-1) with polymer of sialic acid as substrate. {ECO:0000269\|PubMed:19525232};
Subunit:		Homotrimer. {ECO:0000269\|PubMed:19525232}.
Miscellaneous:		Polymeric sialic acid-containing capsule provides a means for the bacteria to evade the immune response during infection by mimicking host sialic acid-containing cell surface structures. O- acetylation of the sialic acid residues of capsular polysaccharides alters their immunogenicity and susceptibility to glycosidases. {ECO:0000303\|PubMed:19525232}.
Similarity:		Belongs to the transferase hexapeptide repeat family. {ECO:0000305}.