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Journal Issue - Volume 11 Issue 1 (January 2002)

Abstract This article presents a comparative analysis of two sets of data from recent experiments on kinetics of (i) protein unfolding by mechanical force and (ii) channel gating with membrane electric potential. Both situations necessitate a continuous Brownian‐dynamic view of protein conformational kinetics. We show that the discrete approach traditional to biochemical kinetics is insufficient for understanding dynamics of protein...

Abstract A nuclear magnetic resonance (NMR) investigation of a fragment of the nonreceptor Tec family tyrosine kinase Btk has revealed an intricate set of coupled monomer‐dimer equilibria. The Btk fragment studied contains two consecutive proline‐rich motifs followed by a single Src homology 3 (SH3) domain. We provide evidence for an asymmetric homodimer in which the amino‐terminal proline sequence of one monomer contacts the...

Abstract Catalases, although synthesized from single genes and built up from only one type of subunit, exist in heterogeneous form with respect to their conformations and association states in biological systems. This heterogeneity is not of genetic origin, but rather reflects the instability of this oligomeric heme enzyme. To understand better the factors that stabilize the various association states of catalase, we performed...

Abstract Pulsed hydrogen exchange methods were used to follow the formation of structure during the refolding of acid‐denatured staphylococcal nuclease containing a stabilizing Leu substitution at position 124 (H124L SNase). The protection of more than 60 backbone amide protons in uniformly 15N‐labeled H124L SNase was monitored as a function of refolding time by heteronuclear two‐dimensional NMR spectroscopy. As found in previous...

Abstract The contribution of solvent‐exposed charged residues to protein stability was evaluated using ubiquitin as a model protein. We combined site‐directed mutagenesis and specific chemical modifications to first replace all Arg residues with Lys, followed by carbomylation of Lys‐amino groups. Under the conditions in which all carboxylic groups are protonated (at pH 2), the chemically modified protein is folded and very stable...