Mycobacteria Encode Active and Inactive Classes of TesB Fatty-Acyl CoA Thioesterases Revealed through Structural and Functional Analysis
| Autor: | Luis E. N. Quadri, Jade K. Forwood, Glennon V. Bythrow, Crystall M.D. Swarbrick, David Aragão, Gabrielle Germain |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Mycobacterium smegmatis Protein domain Gene Expression Sequence alignment Biochemistry Protein Structure Secondary Structure-Activity Relationship 03 medical and health sciences Acyl-CoA chemistry.chemical_compound Protein structure Bacterial Proteins Protein Domains Thioesterase Catalytic Domain Escherichia coli Amino Acid Sequence Protein Structure Quaternary Genetic Association Studies Genetics Aspartic Acid Alanine Sequence Homology Amino Acid 030102 biochemistry & molecular biology biology Hydrolysis Active site Lipid metabolism biology.organism_classification Recombinant Proteins Isoenzymes Kinetics 030104 developmental biology Amino Acid Substitution Palmitoyl-CoA Hydrolase chemistry Mutation biology.protein Acyl Coenzyme A Sequence Alignment Mycobacterium avium Mycobacterium |
| Zdroj: | Biochemistry. 56:1460-1472 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/acs.biochem.6b01049 |
| Popis: | Mycobacteria contain a large number of highly divergent species and exhibit unusual lipid metabolism profiles, believed to play important roles in immune invasion. Thioesterases modulate lipid metabolism through the hydrolysis of activated fatty-acyl CoAs; multiple copies are present in mycobacteria, yet many remain uncharacterized. Here, we undertake a comprehensive structural and functional analysis of a TesB thioesterase from Mycobacterium avium (MaTesB). Structural superposition with other TesB thioesterases reveals that the Asp active site residue, highly conserved across a wide range of TesB thioesterases, is mutated to Ala. Consistent with these structural data, the wild-type enzyme failed to hydrolyze an extensive range of acyl-CoA substrates. Mutation of this residue to an active Asp residue restored activity against a range of medium-chain length fatty-acyl CoA substrates. Interestingly, this Ala mutation is highly conserved across a wide range of Mycobacterium species but not found in any other bacteria or organism. Our structural homology analysis revealed that at least one other TesB acyl-CoA thioesterase also contains an Ala residue at the active site, while two other Mycobacterium TesB thioesterases harbor an Asp residue at the active site. The inactive TesBs display a common quaternary structure that is distinct from that of the active TesB thioesterases. Investigation of the effect of expression of either the catalytically active or inactive MaTesB in Mycobacterium smegmatis exposed, to the best of our knowledge, the first genotype-phenotype association implicating a mycobacterial tesB gene. This is the first report that mycobacteria encode active and inactive forms of thioesterases, the latter of which appear to be unique to mycobacteria. |
| Databáze: | OpenAIRE |
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