Native-state hydrogen-exchange studies of a fragment complex can provide structural information about the isolated fragments

UNSPECIFIED (1999) Native-state hydrogen-exchange studies of a fragment complex can provide structural information about the isolated fragments. In: Proceedings of the National Academy of Sciences of the United States of America, April-1999, Bangalore,India.

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Abstract

Ordered protein complexes are often formed from partially ordered fragments that are difficult to structurally characterize by conventional NMR and crystallographic techniques. We show that concentration-dependent hydrogen exchange studies of a fragment complex can provide structural information about the solution structures of the isolated fragments. This general methodology can be applied to any bimolecular or multimeric system. The experimental system used here consists of Ribonuclease S, a complex of two fragments of Ribonuclease A. Ribonuclease S and Ribonuclease A have identical three-dimensional structures but exhibit significant differences in their dynamics and stability. We show that the apparent large dynamic differences between Ribonuclease A and Ribonuclease S are caused by small amounts of free fragments in equilibrium with the folded complex, and that amide exchange rates in Ribonuclease S can be used to determine corresponding rates in the isolated fragments. The studies suggest that folded RNase A and the RNase S complex exhibit very similar dynamic behavior. Thus cleavage of a protein chain at a single site need not be accompanied by a large increase in flexibility of the complex relative to that of the uncleaved protein.

Item Type:	Conference Proceedings
Publisher:	National Academy of Sciences
Additional Information:	copyright of this conference paper belongs to National Academy of Sciences
Keywords:	Biochemistry;Molecular Biophysics
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Physical & Mathematical Sciences > Physics
Date Deposited:	17 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12114

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