Repressor gene, <i>blaI</i>, for <i>Bacillus licheniformis</i> 749 β‐lactamase

Nicholls, N; Lampen, J. O.

doi:10.1016/0014-5793(87)80375-7

Cited by 6 publications

(5 citation statements)

References 18 publications

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“…In both strains, the regulation of β‐lactamase production involves three regulatory genes, blaI, blaR1 and blaR2 . The first two genes encode, a repressor and a penicillin sensory transducer respectively, whereas the third is not yet identified (Sherrat and Collins, 1973; Dyke, 1979; Kobayashi et al ., 1987; Nicholls and Lampen, 1987; Rowland and Dyke, 1990). In Bacillus licheniformis 749/I, blaI and blaR1 are located on the chromosome downstream the structural blaP gene and are transcribed in the opposite direction.…”

Section: Introductionmentioning

confidence: 99%

The kinetic properties of the carboxy terminal domain of the Bacillus licheniformis 749/I BlaR penicillin‐receptor shed a new light on the derepression of β‐lactamase synthesis

Duval

Swinnen

Lepage

et al. 2003

Molecular Microbiology

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Section: Introductionmentioning

confidence: 99%

The kinetic properties of the carboxy terminal domain of the Bacillus licheniformis 749/I BlaR penicillin‐receptor shed a new light on the derepression of β‐lactamase synthesis

Duval

Swinnen

Lepage

et al. 2003

Molecular Microbiology

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“…The Bacillus licheniformis 749/I BlaP and Staphylococcus aureus BlaZ class A β‐lactamases are inducible by β‐lactam antibiotics (Joris et al , 1994; Philippon et al , 1998). In both strains, β‐lactamase expression is under the control of two gene products, BlaI and BlaR1, which are a repressor and a penicillin‐sensory transducer respectively (Kobayashi et al , 1987; Nicholls and Lampen, 1987; Rowland and Dyke, 1990) At the DNA level, blaZ/blaP , blaR 1 and blaI are organized as a divergon ( bla divergon) in which blaR 1 and blaI form an operon. It has been shown that purified BlaI is present as a dimer in solution, that the DNA‐binding domain is located near the N‐terminal end and that the dimerization domain is in the C‐terminal region (Wittman et al , 1993).…”

Section: Introductionmentioning

confidence: 99%

The fate of the BlaI repressor during the induction of the Bacillus licheniformis BlaP β‐lactamase

Filée

Benlafya

Delmarcelle

et al. 2002

Molecular Microbiology

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“…5 The blaP gene encodes the class A ␤-lactamase of Bacillus licheniformis 749/I. In the absence of ␤-lactams antibiotics, the BlaI repressor prevents the transcription of the blaP gene (1)(2)(3). Two additional genes, blaR1 and blaR2, are also involved in the induction of the ␤-lactamase synthesis (4,5).…”

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Dimerization and DNA Binding Properties of theBacillus licheniformis 749/I BlaI Repressor

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Vreuls

Herman

et al. 2003

Journal of Biological Chemistry

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In the absence of penicillin, the ␤-lactamase encoding gene blaP of Bacillus licheniformis 749/I is negatively regulated by the transcriptional repressor BlaI. Three palindromic operator regions are recognized by BlaI: two in the blaP promoter (OP1 and OP2) and one (OP3) in the promoter of the blaI-blaR1 operon. In this study, the dissociation constant of the purified BlaI dimer was estimated at 25 M by equilibrium ultracentrifugation. Quantitative Western blot analysis indicates that the intracellular concentrations of BlaI in B. licheniformis 749/I and Bacillus subtilis transformed by a multicopy plasmid harboring the ␤-lactamase locus (blaP-blaIblaR1) were lower than (1.9 M) or in the same range as (75 M) the dissociation constant, respectively. This suggests that BlaI is partially dimeric in the cytoplasm of these strains and interacts in vivo with its operators as a preformed dimer. This hypothesis is supported by band shift assays on an operator containing a randomized half-operator sequence. The global dissociation constants of the operator-BlaI dimer complexes were measured by band shift assays and estimated as K dOP1 ‫؍‬ 1.7 ؎ 0.5 10 The blaP gene encodes the class A ␤-lactamase of Bacillus licheniformis 749/I. In the absence of ␤-lactams antibiotics, the BlaI repressor prevents the transcription of the blaP gene (1-3). Two additional genes, blaR1 and blaR2, are also involved in the induction of the ␤-lactamase synthesis (4, 5). The blaP, blaI, and blaR1 genes are clustered in a divergeon (bla divergeon) in which blaI and blaR1 form an operon (Fig. 1). The blaR1 gene encodes a transmembrane protein that acts as penicillin receptor (6 -8), and blaR2 is not identified yet and is not linked to the bla divergeon. The BlaR2 protein is essential for the inactivation of BlaI. In Staphylococcus aureus, the blaZ and mecA genes, encoding respectively a ␤-lactamase and the low affinity penicillinbinding protein 2Ј, are regulated by similar elements (9, 10).The blaI gene encodes a 128-residue protein characterized by two functional and separate domains (11). The DNA-binding domain, a helix-turn-helix recognition motif, is located in the N-terminal region, and the dimerization domain is in the Cterminal region. After deletion of the C-terminal domain, the repressor becomes unable to dimerize and to form a stable complex with its operators. DNase footprinting experiments and filter binding reactions revealed the presence of three regulatory regions that are recognized specifically by BlaI (11). These operators present a 23-bp-long dyad symmetry and show the deduced 5Ј-AAAGTATTACATATGTAACNTTT-3Ј consensus sequence (Fig. 1).In the presence of ␤-lactam antibiotics, the C-terminal domain of BlaR1 is acylated (6, 7). This event triggers the activation of the putative cytoplasmic metalloprotease motif of BlaR1 by self-proteolysis (8, 12). In S. aureus, the ␤-lactamase induction correlates with BlaI proteolysis between residues Asn 101 and Phe 102 , and it is postulated that the activated form of BlaR1 proteolyses BlaI (12-...

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Repressor gene, blaI, for Bacillus licheniformis 749 β‐lactamase

Cited by 6 publications

References 18 publications

The kinetic properties of the carboxy terminal domain of the Bacillus licheniformis 749/I BlaR penicillin‐receptor shed a new light on the derepression of β‐lactamase synthesis

The kinetic properties of the carboxy terminal domain of the Bacillus licheniformis 749/I BlaR penicillin‐receptor shed a new light on the derepression of β‐lactamase synthesis

The fate of the BlaI repressor during the induction of the Bacillus licheniformis BlaP β‐lactamase

Dimerization and DNA Binding Properties of theBacillus licheniformis 749/I BlaI Repressor

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