The signaling pathway in histidine kinase and the response regulator complex revealed by X-ray crystallography and solution scattering.
J Mol Biol
; 362(1): 123-39, 2006 Sep 08.
Article
en En
| MEDLINE
| ID: mdl-16890956
ABSTRACT
The structure of a histidine kinase (ThkA) complexed with a response regulator (TrrA) in the two-component regulatory system from hyperthermophile Thermotoga maritima was determined by a combination of X-ray crystallography at a resolution of 4.2 A and small-angle X-ray scattering (SAXS). The boundary of the three component domains (PAS-sensor, dimerization and catalytic domains) of ThkA and the bound TrrA molecule were unambiguously assigned in the electron density map at 4.2 A resolution. ThkA forms a dimer with crystallographic 2-fold symmetry and two monomeric TrrAs bind to the ThkA dimer. SAXS experiments also confirmed this association state in solution and specific binding between ThkA and TrrA (Kd=8.2x10(-11) M(-2)). The association interface between ThkA and TrrA contains the phosphotransfer His residue in the ThkA, indicative of an efficient receipt of the phosphoryl group. One Per-Arnt-Sim (PAS) domain does not interact with the other PAS domain, but with the catalytic domain of the same polypeptide chain and with one TrrA molecule. Observed inter-domain and inter-molecular interactions reveal a definite pathway of signal transduction in the kinase/regulator complex. In addition, we propose a responsible role of TrrA for the feedback regulation of sensing and/or kinase activities of ThkA.
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Bases de datos:
MEDLINE
Asunto principal:
Proteínas Quinasas
/
Proteínas Bacterianas
/
Transducción de Señal
/
Thermotoga maritima
Idioma:
En
Revista:
J Mol Biol
Año:
2006
Tipo del documento:
Article
País de afiliación:
Japón