Document Detail

Temperature stability of proteins essential for the intracellular survival of Mycobacterium tuberculosis.
MedLine Citation:
PMID:  19014350     Owner:  NLM     Status:  MEDLINE    
In Mycobacterium tuberculosis, the genes hsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) and nat (arylamine N-acetyltransferase) are essential for survival inside of host macrophages. These genes act as an operon and have been suggested to be involved in cholesterol metabolism. However, the role of NAT in this catabolic pathway has not been determined. In an effort to better understand the function of these proteins, we have expressed, purified and characterized TBNAT (NAT from M. tuberculosis) and HsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) from M. tuberculosis. Both proteins demonstrated remarkable heat stability with TBNAT and HsaD retaining >95% of their activity after incubation at 60 degrees C for 30 min. The first and second domains of TBNAT were demonstrated to be very important to the heat stability of the protein, as the transfer of these domains caused a dramatic reduction in the heat stability. The specific activity of TBNAT was tested against a broad range of acyl-CoA cofactors using hydralazine as a substrate. TBNAT was found to be able to utilize not just acetyl-CoA, but also n-propionyl-CoA and acetoacetyl-CoA, although at a lower rate. As propionyl-CoA is a product of cholesterol catabolism, we propose that NAT could have a role in the utilization of this important cofactor.
Nathan A Lack; Akane Kawamura; Elizabeth Fullam; Nicola Laurieri; Stacey Beard; Angela J Russell; Dimitrios Evangelopoulos; Isaac Westwood; Edith Sim
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Biochemical journal     Volume:  418     ISSN:  1470-8728     ISO Abbreviation:  Biochem. J.     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-02-06     Completed Date:  2009-03-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  England    
Other Details:
Languages:  eng     Pagination:  369-78     Citation Subset:  IM    
Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX13QT, UK.
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MeSH Terms
Arylamine N-Acetyltransferase / chemistry,  genetics,  metabolism
Bacterial Proteins / chemistry,  genetics,  metabolism
Cholesterol / metabolism
Coenzyme A / chemistry,  metabolism
Hydrolases / genetics,  isolation & purification,  metabolism
Intracellular Space / metabolism
Metabolic Networks and Pathways / genetics
Microbial Viability* / genetics
Models, Biological
Mycobacterium tuberculosis / genetics,  metabolism,  physiology*
Protein Processing, Post-Translational / genetics
Protein Stability*
Recombinant Proteins / genetics,  metabolism
Grant Support
//Wellcome Trust
Reg. No./Substance:
0/Bacterial Proteins; 0/Recombinant Proteins; 57-88-5/Cholesterol; 85-61-0/Coenzyme A; EC N-Acetyltransferase; EC 3.-/Hydrolases; EC 3.7.-/HsaD protein, Mycobacterium tuberculosis

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