Thermostability of the barnase—barstar complex

FEBS Letters

Yakovlev, G.I.²  Hartley, R.W.¹  Briand, C.M.³  Makarov, A.A.²  Lobachov, V.M.²  Protasevich, I.I.²  Gilli, R.M.³  Kirpichnikov, M.P.² 

[1] National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA;Engelhardt Institute of Molecular Biology, Acad. Sci. Russia, Moscow 117984, Russian Federation;Groupe de Recherche sur les Interactions des Protéines en Pharmacologie, Faculté de Pharmacie, Marseille 13385, France

关键词: Barnase—barstar complex;    Heat denaturation;    Scanning microcalorimetry;    Isothermal microcalorimetry;   

DOI  :  10.1016/0014-5793(94)01127-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Scanning microcalorimetry was used to study heat denaturation of barnase in complex with its intracellular inhibitor barstar. The heat denaturation of the barnase—barstar complex is well approximated by two two-state transitions with the lower temperature transition corresponding to barstar denaturation and the higher temperature one to barnase denaturation. The temperature of barnase melting in its complex with barstar is 20°C higher than that of the free enzyme. The barstar melting temperature is almost the same in the complex or alone (71°C at pH 6.2 and 68°C at pH 8.0). It seems possible that when barstar unfolds it can remain bound to barnase, while the latter unfolds only on dissociation of the denatured barstar.

【 授权许可】

Unknown