Regulation of Response Regulator Autophosphorylation through Interdomain Contacts

Journal Article · Fri Jan 01 00:00:00 EST 2010 · Journal of Biological Chemistry

DOI:https://doi.org/10.1074/jbc.M110.157164· OSTI ID:1019670

Barbieri, C; Mack, T; Robinson, V; Miller, M; Stock, A

DNA-binding response regulators (RRs) of the OmpR/PhoB subfamily alternate between inactive and active conformational states, with the latter having enhanced DNA-binding affinity. Phosphorylation of an aspartate residue in the receiver domain, usually via phosphotransfer from a cognate histidine kinase, stabilizes the active conformation. Many of the available structures of inactive OmpR/PhoB family proteins exhibit extensive interfaces between the N-terminal receiver and C-terminal DNA-binding domains. These interfaces invariably involve the {alpha}4-{beta}5-{alpha}5 face of the receiver domain, the locus of the largest differences between inactive and active conformations and the surface that mediates dimerization of receiver domains in the active state. Structures of receiver domain dimers of DrrB, DrrD, and MtrA have been determined, and phosphorylation kinetics were analyzed. Analysis of phosphotransfer from small molecule phosphodonors has revealed large differences in autophosphorylation rates among OmpR/PhoB RRs. RRs with substantial domain interfaces exhibit slow rates of phosphorylation. Rates are greatly increased in isolated receiver domain constructs. Such differences are not observed between autophosphorylation rates of full-length and isolated receiver domains of a RR that lacks interdomain interfaces, and they are not observed in histidine kinase-mediated phosphotransfer. These findings suggest that domain interfaces restrict receiver domain conformational dynamics, stabilizing an inactive conformation that is catalytically incompetent for phosphotransfer from small molecule phosphodonors. Inhibition of phosphotransfer by domain interfaces provides an explanation for the observation that some RRs cannot be phosphorylated by small molecule phosphodonors in vitro and provides a potential mechanism for insulating some RRs from small molecule-mediated phosphorylation in vivo.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: DE-AC02-98CH10886
• OSTI ID: 1019670
• Report Number(s): BNL-95516-2011-JA; JBCHA3; TRN: US201115%%310
• Journal Information: Journal of Biological Chemistry, Vol. 285, Issue 42; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
AFFINITY
CRYSTAL STRUCTURE
DIMERIZATION
DIMERS
ENZYMES
HISTIDINE
IN VITRO
IN VIVO
KINETICS
PHOSPHATES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
PROTEINS
REGULATIONS
RESIDUES
national synchrotron light source