Comparative study between macrolide regulatory proteins MphR(A) and MphR(E) in ligand identification and DNA binding based on the rapid in vitro detection system

The macrolide regulatory protein MphR(A) has been widely studied and used in various aspects such as metabolism monitoring, exogenous gene expression, and in vivo and in vitro macrolide antibiotic screening. Another macrolide regulatory protein, MphR(E), has rarely been reported. In this study, in vitro ELISA-type systems were established for MphR(A) and MphR(E) to study their correlation. The reactivity of 14 macrolide antibiotics and pseudo-macrolide antibiotics was tested in the systems. The results indicated that the ligand identification spectra of MphR(A) and MphR(E) were basically consistent. The binding characteristics of MphR(A) and MphR(E) with three corresponding promoter DNA sequences were preliminarily studied. According to the ELISA-type analysis results, MphR(A) and MphR(E) have consistent DNA binding properties, which bind to A-DNA/B-DNA more easily than to C-DNA. This study has confirmed that MphR(E) can bind to the promoter DNA sequences mrx(E) and mph(E) in plasmid pRSB111, and different DNAs can affect the sensitivity of the in vitro detection systems.