Domains in lambda Cro repressor. A calorimetric study.

Y V Griko; V V Rogov; P L Privalov

doi:10.1021/bi00165a022

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Domains in lambda Cro repressor. A calorimetric study.

Y V Griko·V V Rogov·P L Privalov

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Abstract

Thermodynamic properties of a mutant lambda Cro repressor with Cys replacing Val55 were studied calorimetrically. Formation of the S-S cross-link between neighboring Cys55 residues in this dimeric molecule leads to stabilization of a structure formed by the C-terminal parts of the two polypeptide chains, which behave as a single cooperative domain upon protein denaturation by heating. This composite domain is very stable at neutral pH and disrupts at 110 degrees C. The S-S-cross-linked tryptic fragment (residues 22-66), which includes this C-terminal domain, has similar stability. The N-terminal parts of the polypeptide chains do not form any stable structure when isolated, but in S-S-cross-linked dimer, they form a single cooperative block which melts in an all-or-none way 9 degrees C higher than the un-cross-linked protein. The observed cooperation of the distant N-terminal parts in dimer raises questions regarding lambda Cro repressor structure in solution.

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Calorimetry DNA-Binding Proteins Electrophoresis, Polyacrylamide Gel Models, Molecular Repressor Proteins Thermodynamics Transcription Factors Viral Proteins Viral Regulatory and Accessory Proteins X-Ray Diffraction Journal Article Research Support, U.S. Gov't, Non-P.H.S.

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Y V Griko, V V Rogov, P L Privalov. 1992-12-22. Domains in lambda Cro repressor. A calorimetric study.. https://doi.org/10.1021/bi00165a022

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