Mechanism of Action of Neisseria gonorrhoeae O-Acetylpeptidoglycan Esterase, an SGNH Serine Esterase

Pfeffer, John M.; Weadge, Joel T.; Clarke, Anthony J.

doi:10.1074/jbc.m112.436352

Cited by 33 publications

(41 citation statements)

References 32 publications

(32 reference statements)

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“…5, A and B). The spatial positioning of the catalytic center is similar to that of serine esterases (75) and serine proteases (76). The superposition also indicates that Gly-296 is positioned and oriented correctly to participate in oxyanion hole formation in AlgX.…”

Section: N-terminal Domain Has An Sgnh Hydrolase-like Core-mentioning

confidence: 59%

Structural and Functional Characterization of Pseudomonas aeruginosa AlgX

Riley

Weadge

Baker

et al. 2013

Journal of Biological Chemistry

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Background: AlgX is required for the biosynthesis and export of the exopolysaccharide alginate. Results: The structure of AlgX has been determined, and the functional characterization of AlgX and mutant variants has been performed. Conclusion:AlgX contains an SGNH hydrolase-like domain and carbohydrate-binding module. Mutation of the Ser-His-Asp triad in vivo results in non-acetylated alginate. Significance: This is the first structural characterization of a polysaccharide acetyltransferase.

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Section: N-terminal Domain Has An Sgnh Hydrolase-like Core-mentioning

confidence: 59%

Structural and Functional Characterization of Pseudomonas aeruginosa AlgX

Riley

Weadge

Baker

et al. 2013

Journal of Biological Chemistry

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“…The active site of Pp AlgJ 75–370 and the orientation of the putative catalytic triad D190, H192 and S288, is analogous to Pa AlgX 27–474 and other serine esterases and proteases (Figure 3B) [39], [40]. Similar to Pa AlgX 27–474 , the structure of Pp AlgJ 75–370 reveals several differences relative to canonical SGNH hydrolases [32].…”

Section: Resultsmentioning

confidence: 85%

“…Catalytic variants reduced acetylesterase activity by >80%. Although, the complete loss of activity was observed when similar catalytic residues were replaced in AlgX, in vitro residual activity in catalytic variants has been reported in at least one SGNH esterase [40]. The precise reason for residual activity is not clear since there are limited in vitro studies characterizing catalytic triad variants in SGNH hydrolase superfamily members.…”

Section: Discussionmentioning

confidence: 99%

P. aeruginosa SGNH Hydrolase-Like Proteins AlgJ and AlgX Have Similar Topology but Separate and Distinct Roles in Alginate Acetylation

et al. 2014

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The O-acetylation of polysaccharides is a common modification used by pathogenic organisms to protect against external forces. Pseudomonas aeruginosa secretes the anionic, O-acetylated exopolysaccharide alginate during chronic infection in the lungs of cystic fibrosis patients to form the major constituent of a protective biofilm matrix. Four proteins have been implicated in the O-acetylation of alginate, AlgIJF and AlgX. To probe the biological function of AlgJ, we determined its structure to 1.83 Å resolution. AlgJ is a SGNH hydrolase-like protein, which while structurally similar to the N-terminal domain of AlgX exhibits a distinctly different electrostatic surface potential. Consistent with other SGNH hydrolases, we identified a conserved catalytic triad composed of D190, H192 and S288 and demonstrated that AlgJ exhibits acetylesterase activity in vitro. Residues in the AlgJ signature motifs were found to form an extensive network of interactions that are critical for O-acetylation of alginate in vivo. Using two different electrospray ionization mass spectrometry (ESI-MS) assays we compared the abilities of AlgJ and AlgX to bind and acetylate alginate. Binding studies using defined length polymannuronic acid revealed that AlgJ exhibits either weak or no detectable polymer binding while AlgX binds polymannuronic acid specifically in a length-dependent manner. Additionally, AlgX was capable of utilizing the surrogate acetyl-donor 4-nitrophenyl acetate to catalyze the O-acetylation of polymannuronic acid. Our results, combined with previously published in vivo data, suggest that the annotated O-acetyltransferases AlgJ and AlgX have separate and distinct roles in O-acetylation. Our refined model for alginate acetylation places AlgX as the terminal acetlytransferase and provides a rationale for the variability in the number of proteins required for polysaccharide O-acetylation.

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“…C, CD spectra of wild-type E25 and its mutants. It has been demonstrated in esterase Ape1a that mutation on the catalytic Asp reduced the catalytic efficiency without impact on substrate binding, whereas mutation on its catalytic Ser/His resulted in reduction in both substrate binding and catalytic efficiency (31). For E25, R296A and E330A mutations reduced the catalytic efficiency but had little impact on substrate binding, which suggests that these mutations may disturb the catalytic Asp 282 .…”

mentioning

confidence: 99%

Structural Basis for Dimerization and Catalysis of a Novel Esterase from the GTSAG Motif Subfamily of the Bacterial Hormone-sensitive Lipase Family

et al. 2014

Journal of Biological Chemistry

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Mechanism of Action of Neisseria gonorrhoeae O-Acetylpeptidoglycan Esterase, an SGNH Serine Esterase

Cited by 33 publications

References 32 publications

Structural and Functional Characterization of Pseudomonas aeruginosa AlgX

Structural and Functional Characterization of Pseudomonas aeruginosa AlgX

P. aeruginosa SGNH Hydrolase-Like Proteins AlgJ and AlgX Have Similar Topology but Separate and Distinct Roles in Alginate Acetylation

Structural Basis for Dimerization and Catalysis of a Novel Esterase from the GTSAG Motif Subfamily of the Bacterial Hormone-sensitive Lipase Family

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