The Neisseria meningitidis Serogroup A Capsular Polysaccharide O-3 and O-4 Acetyltransferase

Abstract

Neisseria meningitidis serogroup A capsular polysaccharide (CPS) is composed of a homopolymer of O-acetylated, α1→6-linked ManNAc 1-phosphate that is distinct from the capsule structures of the other meningococcal disease-causing serogroups, B, C, Y, and W-135. The serogroup A capsule biosynthetic genetic cassette consists of four open reading frames, mynA–D (sacA–D), that are specific to serogroup A, but the functions of these genes have not been well characterized. mynC was found to encode an inner membrane-associated acetyltransferase that is responsible for the O-acetylation of the CPS of serogroup A. The wild-type CPS as revealed by 1H NMR had 60–70% O-acetylated ManNAc residues that contained acetyl groups at O-3, with some species acetylated at O-4 and at both O-3 and O-4. A non-polar mynC mutant generated by introducing an aphA-3 kanamycin resistance cassette produced CPS with no O-acetylation. A serogroup A capsule-specific monoclonal antibody was shown to recognize the wild-type O-acetylated CPS, but not the CPS of the mynC mutant, which lacked O-acetylation. MynC was C-terminally His-tagged and overexpressed in Escherichia coli to obtain the predicted ∼26-kDa protein. The acetyltransferase activity of purified MynC was demonstrated in vitro using [14C]acetyl-CoA. MynC O-acetylated the O-acetylated CPS of the mynC mutant and further acetylated the wild-type CPS of serogroup A meningococci, but not the CPS of serogroup B or C meningococci. Genetic complementation of the mynC mutant confirmed the function of MynC as the serogroup A CPS O-3 and O-4 acetyltransferase. MynC represents a new subclass of O-acetyltransferases that utilize acetyl-CoA to decorate the d-mannosamine capsule of N. meningitidis serogroup A. Neisseria meningitidis serogroup A capsular polysaccharide (CPS) is composed of a homopolymer of O-acetylated, α1→6-linked ManNAc 1-phosphate that is distinct from the capsule structures of the other meningococcal disease-causing serogroups, B, C, Y, and W-135. The serogroup A capsule biosynthetic genetic cassette consists of four open reading frames, mynA–D (sacA–D), that are specific to serogroup A, but the functions of these genes have not been well characterized. mynC was found to encode an inner membrane-associated acetyltransferase that is responsible for the O-acetylation of the CPS of serogroup A. The wild-type CPS as revealed by 1H NMR had 60–70% O-acetylated ManNAc residues that contained acetyl groups at O-3, with some species acetylated at O-4 and at both O-3 and O-4. A non-polar mynC mutant generated by introducing an aphA-3 kanamycin resistance cassette produced CPS with no O-acetylation. A serogroup A capsule-specific monoclonal antibody was shown to recognize the wild-type O-acetylated CPS, but not the CPS of the mynC mutant, which lacked O-acetylation. MynC was C-terminally His-tagged and overexpressed in Escherichia coli to obtain the predicted ∼26-kDa protein. The acetyltransferase activity of purified MynC was demonstrated in vitro using [14C]acetyl-CoA. MynC O-acetylated the O-acetylated CPS of the mynC mutant and further acetylated the wild-type CPS of serogroup A meningococci, but not the CPS of serogroup B or C meningococci. Genetic complementation of the mynC mutant confirmed the function of MynC as the serogroup A CPS O-3 and O-4 acetyltransferase. MynC represents a new subclass of O-acetyltransferases that utilize acetyl-CoA to decorate the d-mannosamine capsule of N. meningitidis serogroup A. Neisseria meningitidis serogroup A is responsible for the massive epidemics of meningococcal meningitis and septicemia that periodically affect sub-Saharan Africa, China, South America, and other parts of the world. The serogroup A capsular polysaccharide (CPS) 1The abbreviations used are: CPS, capsular polysaccharide; mAb, monoclonal antibody; Ni-NTA, nickel-nitrilotriacetic acid; IPTG, isopropyl-β-d-thiogalactopyranoside; ELISA, enzyme-linked immunosorbent assay. that confers serogroup specificity is composed of repeating units of α1→6-linked ManNAc 1-phosphate that is O-acetylated (1Liu T.Y. Gotschlich E.C. Jonssen E.K. Wysocki J.R. J. Biol. Chem. 1971; 246: 2849-2858Abstract Full Text PDF PubMed Google Scholar). Although there is evidence of other glycosidic linkages (2Bundle D.R. Smith I.C.P. Jennings H.J. J. Biol. Chem. 1974; 249: 2275-2281Abstract Full Text PDF PubMed Google Scholar), the principal linkage between monomer ManNAc residues in this polysaccharide is the α1→6 phosphodiester bond involving the hemiacetal group of carbon 1 and the hydroxyl group of carbon 6 of the mannosamine residues. Serogroup A CPS is structurally distinct from the other disease-causing meningococcal serogroups, B, C, Y, and W-135, which are composed of or contain sialic acid (1Liu T.Y. Gotschlich E.C. Jonssen E.K. Wysocki J.R. J. Biol. Chem. 1971; 246: 2849-2858Abstract Full Text PDF PubMed Google Scholar, 3Bhattacharjee A.K. Jennings H.J. Kenny C.P. Martin A. Smith I.C. Can. J. Biochem. 1976; 54: 1-8Crossref PubMed Scopus (133) Google Scholar, 4Bhattacharjee A.K. Jennings H.J. Kenny C.P. Martin A. Smith I.C.P. J. Biol. Chem. 1975; 250: 1926-1932Abstract Full Text PDF PubMed Google Scholar). Meningococcal serogroups C, Y, W-135, and H also express O-acetylated capsules. Interestingly, the serogroup B CPS is not O-acetylated. The genes encoding the putative CPS O-acetyltransferases OatC and OatWY, responsible for the O-acetylation of meningococcal serogroup C and serogroups W-135 and Y, respectively, have been recently identified (5Claus H. Borrow R. Achtman M. Morelli G. Kantelberg C. Longworth E. Frosch M. Vogel U. Mol. Microbiol. 2004; 51: 227-239Crossref PubMed Scopus (84) Google Scholar). Other pathogens such as pneumococcal serotype 9V, Salmonella enterica serovar typhi Vi, Staphylococcus aureus serotypes 5 and 8, and Escherichia coli K1 (6Orskov F. Orskov I. Sutton A. Schneerson R. Lin W. Egan W. Hoff G.E. Robbins J.B. J. Exp. Med. 1979; 149: 669-685Crossref PubMed Scopus (146) Google Scholar) also express O-acetylated capsules. The biological importance of O-acetylation of CPS appears to be species- or subspecies-dependent. In some pathogens, O-acetylation of capsules is involved in immune recognition (6Orskov F. Orskov I. Sutton A. Schneerson R. Lin W. Egan W. Hoff G.E. Robbins J.B. J. Exp. Med. 1979; 149: 669-685Crossref PubMed Scopus (146) Google Scholar, 7Szu S.C. Li X.R. Stone A.L. Robbins J.B. Infect. Immun. 1991; 59: 4555-4561Crossref PubMed Google Scholar). For meningococcal serogroup A CPS, there is a dramatic reduction in the immunogenicity of the polysaccharide observed upon removal of the O-acetyl groups by chemical treatment (8Berry D.S. Lynn F. Lee C.H. Frasch C.E. Bash M.C. Infect. Immun. 2002; 70: 3707-3713Crossref PubMed Scopus (113) Google Scholar). The general genetic organization of CPS genes of N. meningitidis is similar to that of other bacterial systems such as Haemophilus influenzae, E. coli K1, etc., that are classified (9Roberts I.S. Annu. Rev. Microbiol. 1996; 50: 285-315Crossref PubMed Scopus (525) Google Scholar, 10Whitfield C. Roberts I.S. Mol. Microbiol. 1999; 31: 1307-1319Crossref PubMed Scopus (413) Google Scholar) as group II capsules. It is usually composed of a unique biosynthetic genetic cassette and conserved genes involved in translocation of the CPS. The genetic cassette responsible for the biosynthesis of the serogroup A capsule is composed of an ∼5-kb nucleotide sequence located (Fig. 1) between ctrA, the outer membrane capsule transporter, and galE, the UDP-glucose 4-epimerase (11Swartley J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google Scholar). open reading mynA–D or are as an (11Swartley J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google Scholar) and are not found in the of other meningococcal serogroups or in Neisseria from by a is predicted to encode a acid that to the E. coli been to be the capsule been predicted to be involved in CPS or in of the capsule to the meningococcal (11Swartley J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google Scholar). In this that mynC an that acetyl groups to the ManNAc residues of the serogroup A CPS. and bacterial and used in this are in I. The meningococcal serogroup A an in in F. M. W. E. J. Infect. PubMed Scopus Google Scholar) and by the for and is and was from the of a with is an as a serogroup A from the of an to group and are to that have epidemics in and other parts of the world. antibody J. J.S. PubMed Scopus Google Scholar) the meningococcal serogroup A CPS was by of from acid and monoclonal from The was from at and from sequence was with the and an at the of and used in this meningitidis serogroup A J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google with J. Mol. Biol. PubMed Scopus Google C. J. J. PubMed Scopus Google of aphA-3 R. C. J. PubMed Scopus Google for A. Stephens D.S. J. 2002; PubMed Scopus Google of mynC from and mynC with from and of with of of of J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google A. Stephens D.S. J. 2002; PubMed Scopus Google A. Stephens D.S. J. 2002; PubMed Scopus Google in a new with at with and or in the and with was used kanamycin was The used for E. coli and and for N. meningitidis and E. coli was used for and of by the of A. E. J. Microbiol. 1976; PubMed Google Scholar). E. coli with a to the of Meningococcal mynC of produced by using and (11Swartley J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google Scholar) and the of as a was to The aphA-3 from R. C. J. PubMed Scopus Google Scholar) with and and in with was the unique of mynC in to The of aphA-3 was confirmed by and sequence of was used to meningococcal serogroup A to The of the aphA-3 cassette the mynC sequence was confirmed by with and and of Meningococcal sequence of mynC was by using and The with and was with the to in a was purified and to sequence to the mynC sequence and the was E. coli of of the was with 1 for 5 The in of 1 and 1 for and for with The was by at for at The overexpressed was purified the with a in the was with of of for 1 a The was with 5 of and in and with 5 of The MynC was also and purified using a a with a in the The purified MynC by using and in 5 and 1 The was with a using as the of the of mynC the of the was a meningococcal mynC with a was from using and The was to The mynC was from with and and the and of to with mynC the of the The was confirmed by using and The was with in with and the of the meningococcal The was with and the was used to wild-type and non-polar mynC mutant and Meningococcal and and by the of Infect. Immun. PubMed Google Scholar) from the meningococcal mynC the from a of with 1 IPTG, was used to the inner and outer and The was in of 1 and with 1 for at The with of to and for in an with The was by at for at The was at at for at The the meningococcal membrane was with The of of the membrane with was by the activity of a J. PubMed Google Scholar), for both The membrane The by acid and in of 1 membrane was with of in for 1 at using an inner membrane and outer membrane by at for at The outer membrane was in of 1 The inner membrane by and the was in The the of of meningococcal at 1 and by the of the membrane of membrane as J.B. J. PubMed Google Scholar). the membrane with 5 of and 1 or 6 for at at or and with at for 1 at the in the with and the with and in 1 an of was CPS and was from of meningococcal using the of Gotschlich E.C. Liu T.Y. J. Exp. Med. PubMed Scopus Google Scholar). the with a of a that the The was by and in and was to a of 1 to the polysaccharide from the from the by by CPS in the was by at a of of and other with and a composed of and 5 CPS was further purified by using for by acid M. Chem. Scopus Google Scholar). and by and by and J.S. J. PubMed Google Scholar). and NMR of of purified CPS was the of the the groups by treatment of the purified serogroup A CPS. The by using a 1991; Scholar). wild-type or mutant CPS was in to a of 5 with for at by at for to of the to NMR and in a for to the inner of the NMR NMR a NMR with a and a and the of or a with a and NMR at using a The was at the are as of a of of and a of a of a using the of meningococcal was using a of Mol. Microbiol. PubMed Scopus Google Scholar). with to a of with of A in from in to an of and a was the of the and with 5 of A. A 5 of A was also as a The of both the and was as the of the by that of the and are as a of to the was as Martin L.E. Stephens D.S. Infect. Immun. PubMed Google Scholar) using at a of with a at was used as a A wild-type and mynC mutant and membrane using a of and was with to capsules. with in and Serogroup A capsule-specific J. J.S. PubMed Scopus Google Scholar) was used as the antibody at was used at at for 1 in of and of in and of in using the the to for at and for 1 with in for by a and to as monoclonal used as at using the (11Swartley J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google Scholar) with the at of meningococcal to and at was used at and antibody was used at at of of purified was also to the by S. J. Biol. Chem. Full Text PDF PubMed Google Scholar). of CPS with an of in for at by the of 1 of acid and in acid The from the of O-acetyl groups was at with a of as the activity was with the N. J. PubMed Scopus Google Scholar). MynC at with 5 in in of was at activity was by using as acetyl and purified meningococcal as In a of CPS, of MynC and of specific activity of in composed of 1 and The to a at and in of and of The with for The to at and of purified of and of CPS purified from the non-polar mynC mutant in the was for 1 at the the CPS was with and the was with and using and a The of CPS by MynC was at and the of was to the 5 of purified MynC to the CPS. The with and and the was by the for the MynC a a and a with used in the 5 of purified The was for 1 at of with the MynC acid sequence identified in the with sequence these of of E. D.R. J. C. Microbiol. PubMed Google and a CPS from S. aureus aureus S. J. Lee J. PubMed Google Scholar). Interestingly, these with MynC a of in the and of O-acetyltransferases from and revealed no to of MynC in a new of the MynC sequence at the for and for revealed no in the using the of and no to predicted MynC as a of the which and of the and mynC of the non-polar mynC mutant was not with the of the wild-type the from of similar for CPS the mynC mutant CPS with the wild-type from wild-type and the non-polar mynC mutant and to and The of the removal of the groups by revealed ManNAc as the of from both the wild-type and the mynC by NMR and of the of O-acetylation and the of the O-acetyl the to and 1H NMR of the be from the and NMR The wild-type CPS with C. 1996; PubMed Scopus Google Scholar, C. J. 2002; PubMed Scopus Google Scholar) and with these the mynC mutant CPS was of the and O-acetylated. in a new In the wild-type CPS 1H NMR shown in the of ManNAc was observed at the was acetylated at O-3 to the of the acetyl The of this in the of the mutant CPS (Fig. the of at O-3 the ManNAc The at was observed in the wild-type CPS, in the mynC mutant this was (Fig. A and In the between and and O-acetyl observed (Fig. and identified in the wild-type CPS of these to O-acetyl the other was to in the (Fig. and of the mynC mutant CPS, to the at was the of O-acetylation. in NMR the of O-acetylation in the mynC mutant CPS. The of the CPS from the wild-type and mynC mutant using of the C. 1996; PubMed Scopus Google Scholar, C. J. 2002; PubMed Scopus Google Scholar). of the ManNAc for the revealed that the wild-type CPS of to and to C. 1996; PubMed Scopus Google Scholar), and at a of and this was found to be The CPS of the mynC mutant a at In the of both and in the mutant CPS that MynC is for O-acetylation at both from the of the of the from the wild-type the mynC mutant and the mynC mutant O-acetylated. the of the of the of is to a the of the of the of is to a as the of the of the of is to a C. 1996; PubMed Scopus Google the of the of the of is to a as C. 1996; PubMed Scopus Google Scholar). in a new further the NMR a S. J. Biol. Chem. Full Text PDF PubMed Google Scholar) of O-acetylation of of and of purified from the wild-type and mynC mutant was The wild-type CPS O-acetylation of and the CPS of the mynC mutant of and respectively, of the of the of the acetyltransferase MynC was C-terminally overexpressed in E. and purified by (Fig. by the in the of or by the MynC purified by both and used similar MynC was used in in vitro the serogroup A wild-type or mynC mutant CPS as the and as the acetyl of the (Fig. revealed that MynC the group from acetyl-CoA to the CPS of the mynC mutant (Fig. Interestingly, MynC was also of further the wild-type CPS (Fig. MynC the serogroup A CPS, but not serogroup B or C CPS (Fig. and the acetyltransferase activity was not to the E. coli in the MynC as the of the not activity (Fig. and The observed O-acetylation activity was the function of as the a in the a of of MynC in a (Fig. In MynC demonstrated with the activity at the and not activity (Fig. MynC activity at and the activity also at The for the MynC activity was between and (Fig. and in the in vitro not for the as the and and similar not of the Meningococcal mynC of mynC the of the was and the meningococcal as The was the mynC mutant and the wild-type to and The wild-type the wild-type MynC the mynC mutant, and the with or and by not and (Fig. using the serogroup A capsule-specific The a serogroup A that and in (11Swartley J.S. Liu L.J. Miller Y.K. Martin L.E. Edupuganti S. Stephens D.S. J. PubMed Google Scholar), was used as a The wild-type and by the non-polar mynC mutant and the not with the The non-polar mynC mutant and the was with that an O-acetyl group is a of the specificity of The CPS from the was to 1H NMR which revealed the of O-acetylation in the (Fig. with the of of and the of O-acetylation in the with IPTG, was the wild-type the of the acetylated species was similar to the wild-type In the mynC mutant CPS O-acetylated in vitro by MynC was by not the importance of O-acetylation in the by this In ELISA, 1H and with the CPS from the revealed that O-acetylation was by genetic (Fig. of the from the wild-type and the mynC mutant was also using the MynC (Fig. and was in the upon a with the of O-acetylation in the mutant CPS. MynC to a for for of no in MynC at The mynC was used to the of MynC in serogroup A the of mynC a and of the MynC protein. of the which the of the of meningococci, revealed that MynC was with the inner membrane (Fig. The membrane and inner membrane the and the outer membrane no the with the of the not the that MynC is a or of with 6 the treatment with 1 or (Fig. not MynC from the that MynC is a with the inner The CPS is the in N. and four C, Y, and of the meningococcal disease-causing serogroups express O-acetylated capsules (1Liu T.Y. Gotschlich E.C. Jonssen E.K. Wysocki J.R. J. Biol. Chem. 1971; 246: 2849-2858Abstract Full Text PDF PubMed Google Scholar, 3Bhattacharjee A.K. Jennings H.J. Kenny C.P. Martin A. Smith I.C. Can. J. Biochem. 1976; 54: 1-8Crossref PubMed Scopus (133) Google Scholar, Borrow R. J. Martin S. C. Miller E. Infect. Immun. PubMed Scopus Google Scholar, E. Vogel U. H. S. E. Borrow R. Med. Microbiol. 2002; PubMed Google Scholar). the of the serogroup A CPS biosynthetic mynC and the MynC is for meningococcal serogroup A capsule O-acetylation and was shown to be the O-3 and O-4 ManNAc acetyltransferase. MynC represents a new of O-acetyltransferases with no to other O-acetyltransferases or to the sialic acid meningococcal serogroup C, Y, and W-135 capsule O-acetyltransferases and recently (5Claus H. Borrow R. Achtman M. Morelli G. Kantelberg C. Longworth E. Frosch M. Vogel U. Mol. Microbiol. 2004; 51: 227-239Crossref PubMed Scopus (84) Google Scholar). MynC is an inner membrane-associated protein. Although not have MynC with the inner membrane and was from the membrane by 6 but not by a 1 the of treatment to MynC from the membrane that MynC is not an membrane protein. The of MynC with the inner membrane that this be a of in capsule of bacterial such as and is in pathogens and in and been shown to have and N. E. coli K1, S. S. and express O-acetylated CPS E. Vogel U. H. S. E. Borrow R. Med. Microbiol. 2002; PubMed Google Scholar, I. S. Borrow R. F. 1999; PubMed Scopus Google Scholar). In S. enterica serovar typhi S.C. Li X.R. Stone A.L. Robbins J.B. Infect. Immun. 1991; 59: 4555-4561Crossref PubMed Google Scholar) and E. coli K1 (6Orskov F. Orskov I. Sutton A. Schneerson R. Lin W. Egan W. Hoff G.E. Robbins J.B. J. Exp. Med. 1979; 149: 669-685Crossref PubMed Scopus (146) Google Scholar), the of O-acetylation from CPS in of in meningococcal serogroup C Borrow R. J. Martin S. C. Miller E. Infect. Immun. PubMed Scopus Google Scholar) and pneumococcal serotype Infect. Immun. PubMed Google Scholar), O-acetylation of capsules is not for of In the polysaccharide produced by of from with acid is O-acetylated at and O-3 by and J. 2002; PubMed Scopus Google Scholar). O-acetylation had been shown to to and J. J. PubMed Scopus Google Scholar) and resistance to F. M. M. Infect. Immun. PubMed Scopus Google Scholar). is also for The be O-acetylated at distinct to the specificity and the of the and Mol. Microbiol. PubMed Scopus Google Scholar, J. Mol. Microbiol. PubMed Scopus Google Scholar, J. 1991; PubMed Scopus Google Scholar). In N. and N. meningitidis A. M. A. R. Infect. PubMed Scopus Google Scholar), the hydroxyl of residues in are O-acetylated to both and resistance to are by the immune M. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, N. A. F. J. S. S. M. G. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). A of that an acetyl group from acetyl-CoA to have been identified in and but these sequence of that have been of the J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, A. J. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, A. J. Microbiol. Google Scholar, PubMed Scopus Google Scholar), which the acetyltransferase of such as and the acetyltransferase of E. are that acetyl-CoA as acetyl Interestingly, the sialic acid O-acetyltransferases of meningococcal serogroups W-135 and but not of serogroup C sequence to the (5Claus H. Borrow R. Achtman M. Morelli G. Kantelberg C. Longworth E. Frosch M. Vogel U. Mol. Microbiol. 2004; 51: 227-239Crossref PubMed Scopus (84) Google Scholar). The membrane of this of which such as J. PubMed Google of C. E. U. J. Med. Microbiol. PubMed Scopus Google of Salmonella which the of Lee J. 1996; PubMed Google and which the in R. Mol. Microbiol. PubMed Scopus Google Scholar). other such as the putative capsule O-acetyltransferases of S. serotype and Lee J. 1996; PubMed Google Scholar), the of S. aureus serotype 5 N. A. F. J.S. Lee Mol. Microbiol. PubMed Scopus Google Scholar), and the O-acetylation and of no with the of MynC represents a subclass of that of and of S. aureus aureus S. J. Lee J. PubMed Google Scholar), which is O-acetylated at the acid of the The activity for acid capsule O-acetylation from E. coli K1 was by and A. J. Biol. Chem. Full Text PDF PubMed Google Scholar), but the and the have not been MynC sequence to the that from the C. and a of with MynC a in the contain an conserved to be the the is the G. J. Biochem. PubMed Scopus Google Scholar). purified MynC not activity with the used in other in vitro not N. Mol. Microbiol. PubMed Scopus Google Scholar). is for N. meningitidis serogroup A CPS immunogenicity and antibody (8Berry D.S. Lynn F. Lee C.H. Frasch C.E. Bash M.C. Infect. Immun. 2002; 70: 3707-3713Crossref PubMed Scopus (113) Google Scholar). The by with serogroup A polysaccharide O-acetylation. (8Berry D.S. Lynn F. Lee C.H. Frasch C.E. Bash M.C. Infect. Immun. 2002; 70: 3707-3713Crossref PubMed Scopus (113) Google Scholar) found that A in the of serogroup A are specific for O-acetylated CPS. The importance of O-acetylation in serogroup A capsule immunogenicity was confirmed using O-acetylated and and in immunogenicity with (8Berry D.S. Lynn F. Lee C.H. Frasch C.E. Bash M.C. Infect. Immun. 2002; 70: 3707-3713Crossref PubMed Scopus (113) Google Scholar). in this found that the serogroup A capsule with or O-acetylation the by a of the wild-type and non-polar mynC mutant from with in to the and the and which these not also have a in the of and by N. meningitidis serogroup A. In of meningococcal in a Stephens D.S. I. Infect. Immun. PubMed Scopus Google Scholar), mynC CPS to with the wild-type A. C. R. W. and S. in MynC is specific for meningococcal serogroup A ManNAc CPS. MynC not the sialic acid of N. meningitidis serogroup B or C. The in vitro O-acetylation that MynC the and the O-acetylated CPS as O-acetylation appears to be a of the serogroup A capsular a of capsule by Mol. Microbiol. PubMed Scopus Google Scholar), that the mynC mutant was the and was similar to the wild-type the In the the and the and the demonstrated The and the resistance to by of the mynC mutant that the O-acetylated capsular in the mynC mutant is and the serogroup A capsule and or the of by not O-acetylation. The reduction in of the CPS of the mynC mutant, not biological some of the or of O-acetylation the of CPS in meningococci. In MynC is the CPS O-3 and O-4 acetyltransferase of serogroup A of N. inner membrane-associated acetyl-CoA as the acetyl group and to a new subclass of of the mutant the importance of O-acetylation in serogroup A polysaccharide but O-acetylation is not for capsule or to the from by by MynC be for N. meningitidis serogroup A. The function of MynC be used to the of O-acetylation of serogroup A used for new and meningococcal and polysaccharide E. Martin and for for and the and of for and