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Mutational and structural study of RipA, a key enzyme in Mycobacterium tuberculosis cell division: evidence for the L‐to‐D inversion of configuration of the catalytic cysteine

Mutational and structural study of RipA, a key enzyme in Mycobacterium tuberculosis cell... RipA is a key cysteine protease of Mycobacterium tuberculosis as it is responsible for bacterial daughter‐cell separation. Although it is an important target for antimicrobial development, its mechanism of action and its interaction pattern with its substrate are hitherto unknown. By combining crystallographic and mutational studies with functional assays and molecular modelling, it is shown that the catalytic activity of the enzyme relies on a Cys–His–Glu triad and the impact of the mutation of each residue of the triad on the structure and function of RipA is analysed. Unexpectedly, the crystallographic analyses reveal that mutation of the glutamic acid to alanine results in inversion of the configuration of the catalytic cysteine. The consequent burial of the catalytic cysteine side chain explains the enzyme inactivation upon mutation. These data point to a novel role of the acidic residue often present in the triad of cysteine proteases as a supervisor of cysteine configuration through preservation of the local structural integrity. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Acta Crystallographica Section D: Structural Biology Wiley

Mutational and structural study of RipA, a key enzyme in Mycobacterium tuberculosis cell division: evidence for the L‐to‐D inversion of configuration of the catalytic cysteine

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References (36)

Publisher
Wiley
Copyright
Copyright © 2014 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0907-4449
eISSN
2059-7983
DOI
10.1107/S1399004714013674
pmid
25195744
Publisher site
See Article on Publisher Site

Abstract

RipA is a key cysteine protease of Mycobacterium tuberculosis as it is responsible for bacterial daughter‐cell separation. Although it is an important target for antimicrobial development, its mechanism of action and its interaction pattern with its substrate are hitherto unknown. By combining crystallographic and mutational studies with functional assays and molecular modelling, it is shown that the catalytic activity of the enzyme relies on a Cys–His–Glu triad and the impact of the mutation of each residue of the triad on the structure and function of RipA is analysed. Unexpectedly, the crystallographic analyses reveal that mutation of the glutamic acid to alanine results in inversion of the configuration of the catalytic cysteine. The consequent burial of the catalytic cysteine side chain explains the enzyme inactivation upon mutation. These data point to a novel role of the acidic residue often present in the triad of cysteine proteases as a supervisor of cysteine configuration through preservation of the local structural integrity.

Journal

Acta Crystallographica Section D: Structural Biology – Wiley

Published: Jan 1, 2014

Keywords: ; ;

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