3cyt
From Proteopedia
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. 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 Sun May 4 21:59:52 2008
