1mqv
From Proteopedia
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Crystal Structure of the Q1A/F32W/W72F mutant of Rhodopseudomonas palustris cytochrome c' (prime) expressed in E. coli
Overview
We employed fluorescence energy-transfer probes to investigate the, polypeptide dynamics accompanying cytochrome c' folding. Analysis of, fluorescence energy-transfer kinetics from wild-type Trp-72 or Trp-32 in a, crystallographically characterized (1.78 A) Q1A/F32W/W72F mutant shows, that there is structural heterogeneity in denatured cytochrome c'. Even at, guanidine hydrochloride concentrations well beyond the unfolding, transition, a substantial fraction of the polypeptides ( approximately, 50%) adopts compact conformations (tryptophan-to-heme distance, approximately 25 A) in both pseudo-wild-type (Q1A) and mutant proteins. A, burst phase (< or =5 ms) is revealed when stopped flow-triggered refolding, is probed by tryptophan intensity: measurements on the Q1A protein show, that approximately 75% of the Trp-72 fluorescence (83% for Trp-32) is, quenched within the mixing deadtime, suggesting that most of the, polypeptides have collapsed.
About this Structure
1MQV is a Single protein structure of sequence from Rhodopseudomonas palustris with HEM as ligand. Full crystallographic information is available from OCA.
Reference
Structural features of cytochrome c' folding intermediates revealed by fluorescence energy-transfer kinetics., Lee JC, Engman KC, Tezcan FA, Gray HB, Winkler JR, Proc Natl Acad Sci U S A. 2002 Nov 12;99(23):14778-82. Epub 2002 Oct 29. PMID:12407175
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