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|3cyt, resolution 1.80Å ()|
REDOX CONFORMATION CHANGES IN REFINED TUNA CYTOCHROME C
Tuna ferrocytochrome c and ferricytochrome c have been refined independently at high resolution (1.5 A and 1.8 A) to crystallographic residual errors of 17.3% and 20.8%, respectively. Small but significant conformational differences are seen surrounding a buried water molecule that is hydrogen bonded to Asn-52, Tyr-67, and Thr-78. In the oxidized state, this water molecule is 1.0 A closer to the heme and the heme has moved 0.15 A out of its heme crevice; both changes lead to a more polar microenvironment for the heme. Chemical modification studies, patterns of evolutionary conservatism, structural differences in bacterial cytochromes, and x-ray studies all agree that the "active site" for cytochrome c is bounded by lysines 8, 13,27, 72, 79, 86, and 87 (thus containing the evolutionary conservative 72-87 loop) and has the buried water molecule just below its surface and the opening of the heme crevice slightly to one side.
Redox conformation changes in refined tuna cytochrome c., Takano T, Dickerson RE, Proc Natl Acad Sci U S A. 1980 Nov;77(11):6371-5. PMID:6256733
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
3cyt is a 2 chain structure with sequence from Thunnus alalunga. This structure supersedes the now removed PDB entry 1cyt. The December 2002 RCSB PDB Molecule of the Month feature on Cytochrome c by David S. Goodsell is 10.2210/rcsb_pdb/mom_2002_12. The May 2007 RCSB PDB Molecule of the Month feature on Aconitase and Iron Regulatory Protein 1 by David S. Goodsell is 10.2210/rcsb_pdb/mom_2007_5. Full crystallographic information is available from OCA.
- Takano T, Dickerson RE. Redox conformation changes in refined tuna cytochrome c. Proc Natl Acad Sci U S A. 1980 Nov;77(11):6371-5. PMID:6256733