3cyt
From Proteopedia
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REDOX CONFORMATION CHANGES IN REFINED TUNA CYTOCHROME C
Overview
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.
About this Structure
3CYT is a Single protein structure of sequence from Thunnus alalunga with and as ligands. This structure supersedes the now removed PDB entry 1CYT. The following pages contain interesting information on the relation of 3CYT with [Aconitase and Iron Regulatory Protein 1]. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Thu Feb 21 19:09:05 2008
