Characterization of the Mycobacterial Acyl-CoA Carboxylase Holo Complexes Reveals Their Functional Expansion into Amino Acid Catabolism

PLoS Pathogens

Andrzej Dziembowski¹  Matthias Wilmanns¹  Uwe Sauer²  Carsten Sachse²  Mamadou Daffé³  Hedia Marrakchi³  Daniel Laubitz⁴  Matthias T. Ehebauer⁴  Arjen J. Jakobi⁴  Elke E. Noens⁵  Marie-Antoinette Lanéelle⁶  Bogdan Cichocki⁶  Michael Zimmermann⁷ 

[1] Université Paul Sabatier, Toulouse, France;Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Tuberculosis & Infection Biology Department, Toulouse, France;Department of Genetics & Biotechnology, Warsaw University, Warsaw, Poland;European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany;European Molecular Biology Laboratory, Structural Biology and Computational Biology Programme, Heidelberg, Germany;Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland;Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland

关键词: Mycobacterium tuberculosis;    Leucine;    Operons;    Pseudomonas aeruginosa;    Sequence alignment;    Multiple alignment calculation;    Esters;    Fatty acids;   

DOI  :  10.1371/journal.ppat.1004623

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Biotin-mediated carboxylation of short-chain fatty acid coenzyme A esters is a key step in lipid biosynthesis that is carried out by multienzyme complexes to extend fatty acids by one methylene group. Pathogenic mycobacteria have an unusually high redundancy of carboxyltransferase genes and biotin carboxylase genes, creating multiple combinations of protein/protein complexes of unknown overall composition and functional readout. By combining pull-down assays with mass spectrometry, we identified nine binary protein/protein interactions and four validated holo acyl-coenzyme A carboxylase complexes. We investigated one of these - the AccD1-AccA1 complex from Mycobacterium tuberculosis with hitherto unknown physiological function. Using genetics, metabolomics and biochemistry we found that this complex is involved in branched amino-acid catabolism with methylcrotonyl coenzyme A as the substrate. We then determined its overall architecture by electron microscopy and found it to be a four-layered dodecameric arrangement that matches the overall dimensions of a distantly related methylcrotonyl coenzyme A holo complex. Our data argue in favor of distinct structural requirements for biotin-mediated γ-carboxylation of α−β unsaturated acid esters and will advance the categorization of acyl-coenzyme A carboxylase complexes. Knowledge about the underlying structural/functional relationships will be crucial to make the target category amenable for future biomedical applications.

【 授权许可】

CC BY