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beta-Lactamase and penicillin-binding protein PBP2' mediate staphylococcal resistance to beta-lactam antibiotics, which are otherwise highly clinically effective. Two repressors (BlaI and MecI) regulate expression of these inducible proteins. Here, we present the first solution structure of the 82 amino acid residue DNA-binding domain of Bacillus licheniformis BlaI which is very similar in primary sequence to the medically significant Staphyloccocal BlaI and MecI proteins. This structure is composed of a compact core of three alpha-helices and a three-stranded beta-sheet typical of the winged helix protein (WHP) family. The protein/DNA complex was studied by NMR chemical shift comparison between the free and complexed forms of BlaI. Residues involved in DNA interaction were identified and a WHP canonical model of interaction with the operators is proposed. In this model, specific contacts occur between the base-pairs of the TACA motif and conserved amino acid residues of the repressor helix H3. These results help toward understanding the repression and induction mechanism of the genes coding for beta-lactamase and PBP2'.
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http://dx.doi.org/10.1016/j.jmb.2003.09.005 | DOI Listing |
BMC Genomics
April 2025
Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, Riga, LV-1067, Latvia.
Background: Most habitats on Earth house unfathomable microbial diversity, yet much of it remains uncultured. The same applies to temperate phages, most of which documented to date are predicted purely in silico from the prophage-like genomic regions of the bacteria, lacking any experimental evidence of their functional integrity (e.g.
View Article and Find Full Text PDFmSphere
May 2020
Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
Food Microbiol
September 2019
Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Burgos, Spain. Electronic address:
We report for the first time an oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) associated with a processed food product in Europe. One isolate (MRSA-ST5-type V SCCmec) was found in cheese among 600 food samples confiscated from air passengers from international flights in Vienna Airport (Austria). Type V SCCmec strains do not harbor functional mecI-mecR1 genes and in such strains mecA expression is regulated by the bla system (blaI-blaR1-blaZ).
View Article and Find Full Text PDFChem Sci
January 2018
Department of Chemistry , Indiana University, Bloomington , IN 47405-7102 , USA . Email: ; Email: ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398.
Resistance to copper (Cu) toxicity in the respiratory pathogen is regulated by the Cu-specific metallosensor CopY. CopY is structurally related to the antibiotic-resistance regulatory proteins MecI and BlaI from , but is otherwise poorly characterized. Here we employ a multi-pronged experimental strategy to define the CopY coordination chemistry and the unique mechanism of allosteric activation by Zn(ii) and allosteric inhibition by Cu(i) of promoter DNA binding.
View Article and Find Full Text PDFInt J Microbiol
February 2016
Department of Pharmacognosy, Faculty of Pharmacy, Comenius University, Odbojárov 10, 832 32 Bratislava, Slovakia.
The essential oil (EO) from Salvia sclarea was shown to increase the susceptibility of methicillin resistant Staphylococcus epidermidis (MRSE) isolates to oxacillin. The purpose of this study was to investigate the effect of EO from S. sclarea on expression of mecA gene of MRSE carrying different types of staphylococcal chromosomal cassette (SCCmec) and to evaluate potential synergistic effect of EO with oxacillin.
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