1MQV

Crystal Structure of the Q1A/F32W/W72F mutant of Rhodopseudomonas palustris cytochrome c' (prime) expressed in E. coli

Summary for 1MQV

• Entry DOI: 10.2210/pdb1mqv/pdb
• Related: 1A7V
• Descriptor: CYTOCHROME C', HEME C (3 entities in total)
• Functional Keywords: four-helix bundle, electron transport
• Biological source: Rhodopseudomonas palustris
• Total number of polymer chains: 2
• Total formula weight: 27427.18

Authors

Lee, J.C.,Engman, K.C.,Tezcan, F.A.,Gray, H.B.,Winkler, J.R. (deposition date: 2002-09-17, release date: 2002-11-20, Last modification date: 2021-10-27)

Primary citation

Lee, J.C.,Engman, K.C.,Tezcan, F.A.,Gray, H.B.,Winkler, J.R.
Structural Features of Cytochrome c' Folding Intermediates Revealed by Fluorescence Energy-Transfer Kinetics
Proc.Natl.Acad.Sci.USA, 99:14778-14782, 2002

PubMed Abstract: 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.

PubMed: 12407175
DOI: 10.1073/pnas.192574099

Experimental method

X-RAY DIFFRACTION (1.78 Å)