Probing Reactivity and Substrate Specificity of Both Subunits of the Dimeric Mycobacterium tuberculosis FabH Using alkyl-CoA Disulfide Inhibitors and acyl-CoA Substrates

Authors

Sarbjot Sachdeva, Portland State University
Faik Musayev, Virginia Commonwealth University
Mamoun M. Alhamadsheh, Portland State University
J. Neel Scarsdale, Virginia Commonwealth University
H. Tonie Wright, Virginia Commonwealth UniversityFollow
Kevin A. Reynolds, Portland State UniversityFollow

Sponsor

This work was supported by a grant from the NIH (AI52230).

Document Type

Post-Print

Publication Date

2007

Subjects

Mycobacterium tuberculosis, Fatty acids -- Biosynthesis, Mass spectrometry, Crystals -- Structure

Abstract

The dimeric Mycobacterium tuberculosis FabH (mtFabH) catalyses a Claisen-type condensation between an acyl-CoA and malonyl-acyl carrier protein (ACP) to initiate the Type II fatty acid synthase cycle. To analyze the initial covalent acylation of mtFabH with acyl-CoA, we challenged it with mixture of C6-C20 acyl-CoAs and the ESI-MS analysis showed reaction at both subunits and a strict specificity for C12 acyl CoA. Crystallographic and ESI-MS studies of mtFabH with a decyl-CoA disulfide inhibitor revealed a decyl chain bound in acyl-binding channels of both subunits through disulfide linkage to the active site cysteine. These data provide the first unequivocal evidence that both subunits of mtFabH can react with substrates or inhibitor. The discrepancy between the observed C12 acyl-CoA substrate specificity in the initial acylation step and the higher catalytic efficiency of mtFabH for C18-C20 acyl-CoA substrates in the overall mtFabH catalyzed reaction suggests a role for M. tuberculosis ACP as a specificity determinant in this reaction.

Description

This is the author’s version of a work that was accepted for publication in Bioorganic Chemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Bioorganic Chemistry, Volume 36, Issue 2, April 2008, Pages 85-90 and can be found online at: http://dx.doi.org/10.1016/j.bioorg.2007.11.001.

© 2008. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

DOI

10.1016/j.bioorg.2007.11.001

Persistent Identifier

http://archives.pdx.edu/ds/psu/19458

Citation Details

Sachdeva, Sarbjot; Musayev, Faik; Alhamadsheh, Mamoun M.; Scarsdale, J. Neel; Wright, H. Tonie; and Reynolds, Kevin A., "Probing Reactivity and Substrate Specificity of Both Subunits of the Dimeric Mycobacterium tuberculosis FabH Using alkyl-CoA Disulfide Inhibitors and acyl-CoA Substrates" (2007). Chemistry Faculty Publications and Presentations. 174.
http://archives.pdx.edu/ds/psu/19458