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Mycobacterial OtsA Structures Unveil Substrate Preference Mechanism and Allosteric Regulation by 2-Oxoglutarate and 2-Phosphoglycerate.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Acebrón-García-de-Eulate, Marta 
Verma, Nupur 
Blaszczyk, Michal 

Abstract

Trehalose is an essential disaccharide for mycobacteria and a key constituent of several cell wall glycolipids with fundamental roles in pathogenesis. Mycobacteria possess two pathways for trehalose biosynthesis. However, only the OtsAB pathway was found to be essential in Mycobacterium tuberculosis, with marked growth and virulence defects of OtsA mutants and strict essentiality of OtsB2. Here, we report the first mycobacterial OtsA structures from Mycobacterium thermoresistibile in both apo and ligand-bound forms. Structural information reveals three key residues in the mechanism of substrate preference that were further confirmed by site-directed mutagenesis. Additionally, we identify 2-oxoglutarate and 2-phosphoglycerate as allosteric regulators of OtsA. The structural analysis in this work strongly contributed to define the mechanisms for feedback inhibition, show different conformational states of the enzyme, and map a new allosteric site.IMPORTANCE Mycobacterial infections are a significant source of mortality worldwide, causing millions of deaths annually. Trehalose is a multipurpose disaccharide that plays a fundamental structural role in these organisms as a component of mycolic acids, a molecular hallmark of the cell envelope of mycobacteria. Here, we describe the first mycobacterial OtsA structures. We show mechanisms of substrate preference and show that OtsA is regulated allosterically by 2-oxoglutarate and 2-phosphoglycerate at an interfacial site. These results identify a new allosteric site and provide insight on the regulation of trehalose synthesis through the OtsAB pathway in mycobacteria.

Description

Keywords

Mycobacterium, OtsA, trehalose, trehalose-6-phosphate synthase, Allosteric Regulation, Bacterial Proteins, Gene Expression Regulation, Bacterial, Gene Expression Regulation, Enzymologic, Glucosyltransferases, Glyceric Acids, Ketoglutaric Acids, Mycobacteriaceae, Substrate Specificity, Trehalose

Journal Title

mBio

Conference Name

Journal ISSN

2161-2129
2150-7511

Volume Title

10

Publisher

American Society for Microbiology

Rights

All rights reserved
Sponsorship
Bill & Melinda Gates Foundation (via Foundation for the National Institutes of Health (FNIH)) (BLUN17STB)
Bill and Melinda Gates Foundation (OPP1158806)
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