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Rv0774c, an iron stress inducible, extracellular esterase is involved in immune-suppression associated with altered cytokine and TLR2 expression.
- Source :
-
International journal of medical microbiology : IJMM [Int J Med Microbiol] 2017 Feb; Vol. 307 (2), pp. 126-138. Date of Electronic Publication: 2017 Jan 22. - Publication Year :
- 2017
-
Abstract
- Tuberculosis, one of the leading cause of death from infectious diseases, is caused by Mycobacterium tuberculosis. The genome of M. tuberculosis has been sequenced and nearly 40% of the whole genome sequence was categorized as hypothetical. Rv0774c was annotated as membrane exported hypothetical protein in TB database. In silico analysis revealed that Rv0774c is a paralog of PE-PGRS multi gene family with 100 aa N-terminal domain similar to PE domain of PE-PGRS proteins. Its C-terminal domain is quite different from PGRS domain, having characteristic lipase signature GXSXG & HG and catalytic residues predicted for lipolytic activity. Therefore, DNA coding for Rv0774c (303 aa), its N-terminal (1-100 aa) and C- terminal domain (100-303 aa) were separately cloned from M. tuberculosis and were over expressed in E. coli. Rv0774c gene and its C-terminal lipolytic domain preferably hydrolyzed short chain esters. Though no enzyme activity was observed in N-terminus PE like domain, it was demonstrated to enhance the thermostability of full length Rv0774c. Tetrahydrolipstatin inhibited the enzyme activity and predicted catalytic residues (Ser-185, Asp-255 and His-281) were confirmed by site directed mutagenesis. Rv0774c was secreted out in culture media by M. tuberculosis and was up-regulated in iron limiting conditions. Treatment of THP-1 cells with rRv0774c resulted in a decline in the LPS induced production of NO and expression of iNOS. rRv0774c treated THP-1 cells also showed an enhanced expression of IL-10 and TLR2. On contrary, it suppressed the LPS induced production of IL-12, chemokines MCP-1 and IL-8. Rv0774c inhibited the LPS induced phosphorylation of p38. These observations suggested that Rv0774c could modulate the pro-inflammatory immune response to support intracellular survival of the mycobacterium.<br /> (Copyright © 2017 Elsevier GmbH. All rights reserved.)
- Subjects :
- Bacterial Proteins chemistry
Bacterial Proteins genetics
Catalytic Domain
Cell Line
Cloning, Molecular
DNA Mutational Analysis
Enzyme Stability
Escherichia coli genetics
Escherichia coli metabolism
Esterases chemistry
Esterases genetics
Gene Expression
Host-Pathogen Interactions
Humans
Lipopolysaccharides metabolism
Monocytes drug effects
Monocytes immunology
Mutagenesis, Site-Directed
Substrate Specificity
Temperature
Bacterial Proteins metabolism
Cytokines antagonists & inhibitors
Esterases metabolism
Immunosuppression Therapy
Mycobacterium tuberculosis enzymology
Mycobacterium tuberculosis physiology
Toll-Like Receptor 2 antagonists & inhibitors
Subjects
Details
- Language :
- English
- ISSN :
- 1618-0607
- Volume :
- 307
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- International journal of medical microbiology : IJMM
- Publication Type :
- Academic Journal
- Accession number :
- 28161108
- Full Text :
- https://doi.org/10.1016/j.ijmm.2017.01.003