English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/50981
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

Characterization of the KstR-dependent promoter of the gene for the first step of the cholesterol degradative pathway in Mycobacterium smegmatis

AuthorsUhía, I. ; Galán, Beatriz ; Medrano, Francisco Javier; García, José Luis
Issue Date1-Sep-2011
PublisherSociety for General Microbiology
CitationMicrobiology, 157 (9) : 2670-2680 (2011)
AbstractThe KstR-dependent promoter of the MSMEG_5228 gene of Mycobacterium smegmatis, which encodes the 3-β-hydroxysteroid dehydrogenase (3-β HSDMS) responsible for the first step in the cholesterol degradative pathway, has been characterized. Primer extension analysis of the P5228 promoter showed that the transcription starts at the ATG codon, thus generating a leaderless mRNA lacking a 5′ untranslated region (5′UTR). Footprint analyses demonstrated experimentally that KstR specifically binds to an operator region of 31 nt containing the quasi-palindromic sequence AACTGGAACGTGTTTCAGTT, located between the −5 and −35 positions with respect to the transcription start site. This region overlaps with the −10 and −35 boxes of the P5228 promoter, suggesting that KstR represses MSMEG_5228 transcription by preventing the binding of RNA polymerase. Using a P5228–β-galactosidase fusion we have demonstrated that KstR is able to work as a repressor in a heterologous system like Escherichia coli. A 3D model of the KstR protein revealed folding typical of TetR-type regulators, with two domains, i.e. a DNA-binding N-terminal domain and a regulator-binding C-terminal domain composed of six helices with a long tunnel-shaped hydrophobic pocket that might interact with a putative highly hydrophobic inducer. The finding that similar P5228 promoter regions have been found in all mycobacterial strains examined, with the sole exception of Mycobacterium tuberculosis, provides new clues about the role of cholesterol in the pathogenicity of this micro-organism
Description11 páginas, 6 figuras, 2 tablas -- PAGS nros. 2670-2680
Publisher version (URL)http://dx.doi.org/10.1099/mic.0.049213-0
URIhttp://hdl.handle.net/10261/50981
DOI10.1099/mic.0.049213-0
ISSN1350-0872
E-ISSN1465-2080
Appears in Collections:(CIB) Artículos
Files in This Item:
There are no files associated with this item.
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.