Download MendeleyStructure of the Response Regulator PhoP from Mycobacterium tuberculosis Reveals a Dimer through the Receiver Domain.
Menon, S., Wang, S.(2011) Biochemistry 50: 5948-5957
- PubMed: 21634789
- DOI: https://doi.org/10.1021/bi2005575
- Primary Citation of Related Structures:
3R0J - PubMed Abstract:
The PhoP protein from Mycobacterium tuberculosis is a response regulator of the OmpR/PhoB subfamily, whose structure consists of an N-terminal receiver domain and a C-terminal DNA-binding domain. How the DNA-binding activities are regulated by phosphorylation of the receiver domain remains unclear due to a lack of structural information on the full-length proteins. Here we report the crystal structure of the full-length PhoP of M. tuberculosis. Unlike other known structures of full-length proteins of the same subfamily, PhoP forms a dimer through its receiver domain with the dimer interface involving α4-β5-α5, a common interface for activated receiver domain dimers. However, the switch residues, Thr99 and Tyr118, are in a conformation resembling those of nonactivated receiver domains. The Tyr118 side chain is involved in the dimer interface interactions. The receiver domain is tethered to the DNA-binding domain through a flexible linker and does not impose structural constraints on the DNA-binding domain. This structure suggests that phosphorylation likely facilitates/stabilizes receiver domain dimerization, bringing the DNA-binding domains to close proximity, thereby increasing their binding affinity for direct repeat DNA sequences.
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States.
