Self-association of the histidine kinase CheA as studied by pulsed dipolar ESR spectroscopy.
Biophys J
; 102(9): 2192-201, 2012 May 02.
Article
en En
| MEDLINE
| ID: mdl-22824284
ABSTRACT
Biologically important protein complexes often involve molecular interactions that are low affinity or transient. We apply pulsed dipolar electron spin resonance spectroscopy and site-directed spin labeling in what to our knowledge is a new approach to study aggregation and to identify regions on protein surfaces that participate in weak, but specific molecular interactions. As a test case, we have probed the self-association of the chemotaxis kinase CheA, which forms signaling clusters with chemoreceptors and the coupling protein CheW at the poles of bacterial cells. By measuring the intermolecular dipolar interactions sensed by spin-labels distributed over the protein surface, we show that the soluble CheA kinase aggregates to a small extent through interactions mediated by its regulatory (P5) domain. Direct dipolar distance measurements confirm that a hydrophobic surface at the periphery of P5 subdomain 2 associates CheA dimers in solution. This result is further supported by differential disulfide cross-linking from engineered cysteine reporter sites. We suggest that the periphery of P5 is an interaction site on CheA for other similar hydrophobic surfaces and plays an important role in structuring the signaling particle.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
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Modelos Moleculares
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Espectroscopía de Resonancia por Spin del Electrón
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Proteínas de la Membrana
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Modelos Químicos
Tipo de estudio:
Risk_factors_studies
Idioma:
En
Revista:
Biophys J
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos