Dataset Information

An HlyB-type function is required for expression of the Enterococcus faecalis hemolysin/bacteriocin.

ABSTRACT: The nucleotide sequence of a 3,422-bp internal restriction fragment from the Enterococcus faecalis pAD1 hemolysin/bacteriocin-encoding region was determined. This fragment was associated with expression of hemolysin/bacteriocin component L and contained a 2,142-bp open reading frame. The inferred amino acid sequence revealed a protein which shared extensive similarity with HlyB of the Escherichia coli alpha-hemolysin operon. The inferred protein, CylB, was observed to be independently expressed in E. coli and capable of complementing an insertion mutation in the cloned hemolysin/bacteriocin operon in trans. Despite the extensive similarity to HlyB, CylB was incapable of complementing an insertion mutation in hlyB. Cytolysin determinants possessing an HlyB-type transport function are widely dispersed throughout gram-negative genera. We believe this to be the first example of an HlyB-type protein encoded within a cytolysin determinant from a gram-positive bacterium.

SUBMITTER: Gilmore MS

PROVIDER: S-EPMC313755 | biostudies-other | 1990 Dec

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

An HlyB-type function is required for expression of the Enterococcus faecalis hemolysin/bacteriocin.

Gilmore M S MS Segarra R A RA Booth M C MC

Infection and immunity 19901201 12

The nucleotide sequence of a 3,422-bp internal restriction fragment from the Enterococcus faecalis pAD1 hemolysin/bacteriocin-encoding region was determined. This fragment was associated with expression of hemolysin/bacteriocin component L and contained a 2,142-bp open reading frame. The inferred amino acid sequence revealed a protein which shared extensive similarity with HlyB of the Escherichia coli alpha-hemolysin operon. The inferred protein, CylB, was observed to be independently expressed ...[more]

PMID: 2123826

Similar Datasets

Project description:Enterococcus faecium clinical isolates A902 and BM4538, which were resistant to relatively high levels of vancomycin (128 and 64 microg/ml, respectively) and to low levels of teicoplanin (4 microg/ml), and Enterococcus faecalis clinical isolates BM4539 and BM4540, which were resistant to moderate levels of vancomycin (16 microg/ml) and susceptible to teicoplanin (0.25 microg/ml), were studied. They were constitutively resistant by synthesis of peptidoglycan precursors ending with d-alanyl-d-lactate and harbored a chromosomal vanD gene cluster which was not transferable by conjugation to other enterococci. VanX(D) activity, which is not required in the absence of d-Ala-d-Ala, was low in the four strains, although none of the conserved residues was mutated; and the constitutive VanY(D) activity in the membrane fractions was inhibited by penicillin G. The mutations E(13)G in the region of d-alanine:d-alanine ligase (which is implicated in d-Ala1 binding in A902) and S(319)N of the serine involved in ATP binding in BM4538 and a 7-bp insertion at different locations in BM4539 and BM4540 (which led to putative truncated proteins) led to the production of an impaired enzyme and accounted for the lack of d-Ala-d-Ala-containing peptidoglycan precursors. The same 7-bp insertion in vanS(D) of BM4539 and BM4540 and a 1-bp deletion in vanS(D) of A902, which in each case led to a putative truncated and presumably nonfunctional protein, could account for the constitutive resistance. Strain BM4538, with a functional VanS(D), had a G(140)E mutation in VanR(D) that could be responsible for constitutive glycopeptide resistance. This would represent the first example of constitutive van gene expression due to a mutation in the structural gene for a VanR transcriptional activator. Study of these four additional strains that could be distinguished on the basis of their various assortments of mutations confirmed that all VanD-type strains isolated so far have mutations in the ddl housekeeping gene and in the acquired vanS(D) or vanR(D) gene that lead to constitutive resistance to vancomycin.

Dataset Information

An HlyB-type function is required for expression of the Enterococcus faecalis hemolysin/bacteriocin.

Publications

An HlyB-type function is required for expression of the Enterococcus faecalis hemolysin/bacteriocin.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets