Pentapeptide Repeat Proteins†

Qnr-like pentapeptide repeat proteins in gram-positive bacteria.

OBJECTIVES To study the role of Qnr-like pentapeptide repeat proteins (PRPs) from several gram-positive species with quinolone resistance in vitro. METHODS A PCR-based strategy was used to clone and express genes coding for Qnr-like PRPs in Enterococcus faecalis, Enterococcus faecium, Listeria monocytogenes, Clostridium perfringens, C. difficile, Bacillus cereus and B. subtilis in Escherichia...

DNA Mimicry by Antirestriction and Pentapeptide Repeat (PPR) Proteins

Protein mimicry of DNA is a recently discovered direct mechanism of regulation of DNAdependent enzyme activity by means of proteins that mimic DNA structure and interact with a target enzyme and completely inhibit (or modulate) its activity. DNA-mimicking inhibitor proteins bind directly to the enzyme and thus blocks or alters the activity of the latter. Protein mimicry of DNA was first describ...

Title : Determination of pentapeptide repeat units in the Qnr proteins

Determination of pentapeptide repeat units in Qnr proteins by the structure-based alignment approach.

The Qnr proteins belong to the pentapeptide repeat protein family. Despite each pentapeptide repeat unit being an important structural determinant, accurately determining pentapeptide repeat units in the Qnr proteins through sequence-based alignments has been challenging. In the present study, the pentapeptide repeat units of the nine representative Qnr proteins have been precisely determined v...

Mutational analysis of quinolone resistance in the plasmid-encoded pentapeptide repeat proteins QnrA, QnrB and QnrS.

OBJECTIVES Pentapeptide repeat proteins (PRPs) QnrA, QnrB and QnrS confer reduced susceptibility to quinolones. This study presents an in vitro analysis of the genetic evolution of quinolone resistance mediated by changes in the coding sequences and promoter regions of qnrA1, qnrS1 and qnrB1 genes. METHODS A random mutagenesis technique was used to predict the evolutionary potential of these ...