%A Manjula Ekka
%A Abhisek Mondal
%A Richa Singh
%A Himanshu Sen
%A Saumen Datta
%A Saumya Raychaudhuri
%O Open Access
%J Frontiers in microbiology
%T Arginine 37 of Glycine Linker Dictates Regulatory Function of HapR
%X HapR is designated as a high cell density quorum sensing master regulatory protein of Vibrio cholerae. It is a member of the TetR family protein and functions both as an activator and a repressor by directly communicating with cognate promoters, thus controlling the expression of a plethora of genes in a density-dependent manner. Molecular insights reveal the domain architecture and further unveil the significance of a cross talk between the DNA binding domain and the dimerization domain for the functionality of the wild-type protein. The DNA binding domain is made up of three ?-helices, where a helix-turn-helix motif spans between the helices ?2 and ?3. The essentiality of the glycine-rich linker linking helices ?1 and ?2 came into prominence while unraveling the molecular basis of a natural non-functional variant of HapR. Subsequently, the importance of linker length was demonstrated. The present study, involving a series of biochemical analyses coupled with molecular dynamics simulation, has illustrated the indispensability of a critical arginine within the linker at position 37 contributing to HapR-DNA binding activity.
%K DNA binding; HapR; Vibrio cholerae; arginine; linker; molecular dynamics; quorum sensing.
%V 11
%D 2020
%R 10.3389/fmicb.2020.01949
%I Frontiers Media S.A
%L open2632