1LFM

CRYSTAL STRUCTURE OF COBALT(III)-SUBSTITUTED CYTOCHROME C (TUNA)

Summary for 1LFM

• Entry DOI: 10.2210/pdb1lfm/pdb
• Related: 1I54 1I55 3CYT 5CYT
• Descriptor: CYTOCHROME C, PROTOPORPHYRIN IX CONTAINING CO (3 entities in total)
• Functional Keywords: cytochrome c, folding, intermediates, electron transport
• Biological source: Thunnus thynnus (bluefin tuna)
• Cellular location: Mitochondrion matrix: P81459
• Total number of polymer chains: 2
• Total formula weight: 24019.30

Authors

Tezcan, F.A.,Findley, W.M.,Crane, B.R.,Ross, S.A.,Lyubovitsky, J.G.,Gray, H.B.,Winkler, J.R. (deposition date: 2002-04-11, release date: 2002-07-19, Last modification date: 2023-08-16)

Primary citation

Tezcan, F.A.,Findley, W.M.,Crane, B.R.,Ross, S.A.,Lyubovitsky, J.G.,Gray, H.B.,Winkler, J.R.
Using deeply trapped intermediates to map the cytochrome c folding landscape.
Proc.Natl.Acad.Sci.USA, 99:8626-8630, 2002

PubMed Abstract: Replacement of iron with cobalt(III) selectively introduces a deep trap in the folding-energy landscape of the heme protein cytochrome c. Remarkably, neither the protein structure nor the folding thermodynamics is perturbed by this metal-ion substitution, as shown by data from spectroscopic and x-ray diffraction experiments. Through kinetics measurements, we have found parallel folding pathways involving several different misligated Co(III) species, and, as these folding intermediates persist for several hours under certain conditions, we have been able to elucidate fully their spectroscopic properties. The results, along with an analysis of the fluorescence energy-transfer kinetics during refolding, show that rapidly equilibrating populations of compact and extended polypeptide conformations are present until all molecules have reached the native structure. These measurements provide direct evidence that collapsed denatured structures are not substantially more stable than extended conformations of cytochrome c.

PubMed: 12084923
DOI: 10.1073/pnas.132254499

Experimental method

X-RAY DIFFRACTION (1.5 Å)