Conformational change of the Bordetella response regulator BvgA accompanies its activation of the B. pertussis virulence gene fhaB

David Kim; John Tracey; Manuel Becerra Flores; Kanita Chaudhry; Rafae Nasim; Abraham Correa-Medina; Leslie Knipling; Qing Chen; Scott Stibitz; Lisa M M Jenkins; Kyung Moon; Tim Cardozo; Deborah M Hinton

doi:10.1016/j.csbj.2022.10.042

Conformational change of the Bordetella response regulator BvgA accompanies its activation of the B. pertussis virulence gene fhaB

Comput Struct Biotechnol J. 2022 Nov 6:20:6431-6442. doi: 10.1016/j.csbj.2022.10.042. eCollection 2022.

Affiliations

¹ Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
² Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York University Grossman School of Medicine, 455 First Avenue, New York, NY 10016, USA.
³ Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA.
⁴ Collaborative Protein Technology Resource, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Abstract

The BvgAS two-component system regulates virulence gene expression in Bordetella pertussis. Although precise three-dimensional structural information is not available for the response regulator BvgA, its sequence conservation with E. coli NarL and previous studies have indicated that it is composed of 3 domains: an N-terminal domain (NTD) containing the phosphorylation site, a linker, and a DNA-binding C-terminal domain (CTD). Previous work has determined how BvgA^CTD dimers interact with the promoter (P _fhaB ) of fhaB, the gene encoding the virulence adhesin filamentous hemagglutinin. Here we use molecular modeling, FeBABE footprinting, and crosslinking to show that within the transcription complex of phosphorylated BvgA (BvgA ∼ P), B. pertussis RNAP, and P _fhaB , the NTDs displace from the CTDs and are positioned at specific locations relative to the three BvgA ∼ P binding sites. Our work identifies a patch of the NTD that faces the DNA and suggests that BvgA ∼ P undergoes a conformational rearrangement that relocates the NTD to allow productive interaction of the CTD with the DNA.

Keywords: BMB, 1,4-bismaleimidobutane; Bordetella pertussis; BvgA; CTD, C-terminal domain; FeBABE; FeBABE, iron bromoacetamidobenzyl-EDTA; Fha, filamentous hemagglutinin; NTD, N-terminal domain; RNAP, RNA polymerase; RR, response regulator; Response regulator; SK, sensor kinase; TCS, two component system; TSS, transcription start site; Two-component system.