The pentapeptide-repeat protein, MfpA, interacts with mycobacterial DNA gyrase as a DNA T-segment mimic
Lipeng Feng, Julia E. A. Mundy, Clare E. M. Stevenson, Lesley A. Mitchenall, David M. Lawson, Kaixia Mi, Anthony Maxwell
Abstract
Significance Pentapeptide-repeat proteins, such as MfpA and Qnr proteins, have an intriguing right-handed quadrilateral β-helical fold that gives rise to an elongated roughly cylindrical structure that resembles the shape of a double-stranded DNA helix. It has been speculated that these proteins, particularly those that interact with bacterial DNA gyrase, act as DNA mimics, competing with DNA to fulfil their functions. Until now there has been no direct evidence for this. Using enzymology and X-ray crystallography, we show the mycobacterial MfpA appears to act as a mimic of the transported (T) DNA segment during the gyrase supercoiling cycle, protecting the enzyme from fluoroquinolone antibiotics. These data suggest a mechanism to limit fluoroquinolone efficacy.