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Title: Structure of N-acetyl-[beta]-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline

Abstract

The crystal structure of GcnA, an N-acetyl-{beta}-D-glucosaminidase from Streptococcus gordonii, was solved by multiple wavelength anomalous dispersion phasing using crystals of selenomethionine-substituted protein. GcnA is a homodimer with subunits each comprised of three domains. The structure of the C-terminal {alpha}-helical domain has not been observed previously and forms a large dimerization interface. The fold of the N-terminal domain is observed in all structurally related glycosidases although its function is unknown. The central domain has a canonical ({beta}/{alpha}){sub 8} TIM-barrel fold which harbours the active site. The primary sequence and structure of this central domain identifies the enzyme as a family 20 glycosidase. Key residues implicated in catalysis have different conformations in two different crystal forms, which probably represent active and inactive conformations of the enzyme. The catalytic mechanism for this class of glycoside hydrolase, where the substrate rather than the enzyme provides the cleavage-inducing nucleophile, has been confirmed by the structure of GcnA complexed with a putative reaction intermediate analogue, N-acetyl-{beta}-D-glucosamine-thiazoline. The catalytic mechanism is discussed in light of these and other family 20 structures.

Authors:
; ; ; ; ;  [1]
  1. Sydney
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1006816
Resource Type:
Journal Article
Journal Name:
J. Mol. Biol.
Additional Journal Information:
Journal Volume: 377; Journal Issue: (1) ; 03, 2008; Journal ID: ISSN 0022-2836
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; ENZYMES; CRYSTAL STRUCTURE; COMPLEXES; ENZYME INHIBITORS; DIMERIZATION; PATHOGENS; REACTION INTERMEDIATES; RESIDUES; STREPTOCOCCUS

Citation Formats

Langley, David B, Harty, Derek W.S., Jacques, Nicholas A, Hunter, Neil, Guss, J Mitchell, Collyer, Charles A, and Westmead). Structure of N-acetyl-[beta]-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline. United States: N. p., 2008. Web. doi:10.1016/j.jmb.2007.09.028.
Langley, David B, Harty, Derek W.S., Jacques, Nicholas A, Hunter, Neil, Guss, J Mitchell, Collyer, Charles A, & Westmead). Structure of N-acetyl-[beta]-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline. United States. doi:10.1016/j.jmb.2007.09.028.
Langley, David B, Harty, Derek W.S., Jacques, Nicholas A, Hunter, Neil, Guss, J Mitchell, Collyer, Charles A, and Westmead). Wed . "Structure of N-acetyl-[beta]-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline". United States. doi:10.1016/j.jmb.2007.09.028.
@article{osti_1006816,
title = {Structure of N-acetyl-[beta]-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline},
author = {Langley, David B and Harty, Derek W.S. and Jacques, Nicholas A and Hunter, Neil and Guss, J Mitchell and Collyer, Charles A and Westmead)},
abstractNote = {The crystal structure of GcnA, an N-acetyl-{beta}-D-glucosaminidase from Streptococcus gordonii, was solved by multiple wavelength anomalous dispersion phasing using crystals of selenomethionine-substituted protein. GcnA is a homodimer with subunits each comprised of three domains. The structure of the C-terminal {alpha}-helical domain has not been observed previously and forms a large dimerization interface. The fold of the N-terminal domain is observed in all structurally related glycosidases although its function is unknown. The central domain has a canonical ({beta}/{alpha}){sub 8} TIM-barrel fold which harbours the active site. The primary sequence and structure of this central domain identifies the enzyme as a family 20 glycosidase. Key residues implicated in catalysis have different conformations in two different crystal forms, which probably represent active and inactive conformations of the enzyme. The catalytic mechanism for this class of glycoside hydrolase, where the substrate rather than the enzyme provides the cleavage-inducing nucleophile, has been confirmed by the structure of GcnA complexed with a putative reaction intermediate analogue, N-acetyl-{beta}-D-glucosamine-thiazoline. The catalytic mechanism is discussed in light of these and other family 20 structures.},
doi = {10.1016/j.jmb.2007.09.028},
journal = {J. Mol. Biol.},
issn = {0022-2836},
number = (1) ; 03, 2008,
volume = 377,
place = {United States},
year = {2008},
month = {9}
}