Key role of barstar Cys‐40 residue in the mechanism of heat denaturation of bacterial ribonuclease complexes with barstar

FEBS Letters

Protasevich, I.I³  Kirpichnikov, M.P¹  Makarov, A.A³  Vasilieva, L.I¹  Polyakov, K.M⁴  Lobachov, V.M³  Hartley, R.W²  Schulga, A.A¹ 

[1] Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117871 Moscow, Russia;National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA;Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 117984 Moscow, Russia;Institute of Crystallography, Russian Academy of Sciences, 117333 Moscow, Russia

关键词: Barnase;    Binase;    Barstar mutant;    Protein-protein complex;    Thermal denaturation;   

DOI  :  10.1016/S0014-5793(99)00158-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The mechanism by which barnase and binase are stabilized in their complexes with barstar and the role of the Cys-40 residue of barstar in that stabilization have been investigated by scanning microcalorimetry. Melting of ribonuclease complexes with barstar and its Cys-82-Ala mutant is described by two 2-state transitions. The lower-temperature one corresponds to barstar denaturation and the higher-temperature transition to ribonuclease melting. The barstar mutation Cys-40-Ala, which is within the principal barnase-binding region of barstar, simplifies the melting to a single 2-state transition. The presence of residue Cys-40 in barstar results in additional stabilization of ribonuclease in the complex.

【 授权许可】

Unknown