2bc5
From Proteopedia
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Crystal structure of E. coli cytochrome b562 with engineered c-type heme linkages
Overview
The four-helix-bundle protein fold can be constructed from a wide variety, of primary amino acid sequences. Proteins with this structure are, excellent candidates for investigations of the relationship between, folding mechanism and topology. The folding of cytochrome b(562), a, four-helix-bundle heme protein, is hampered by heme dissociation. To, overcome this complication, we have engineered a variant of cytochrome, b(562) (cyt c-b(562)) featuring a c-type linkage between the heme and the, polypeptide chain. The replacement of the native cyt b(562) leader, sequence in this protein with that of a c-type cytochrome (cyt c(556)) led, to high yields of fully matured and correctly folded cyt c-b(562). We have, determined the X-ray crystal structure of cyt c-b(562) at 2.25 A and, characterized its physical, chemical, and folding properties. These, measurements reveal that the c-type linkage does not perturb the protein, fold or reduction potential of the heme group. The covalent attachment of, the porphyrin to the polypeptide does, however, produce a substantial, change in protein stability and folding kinetics.
About this Structure
2BC5 is a Single protein structure of sequence from Escherichia coli with SO4 and HEM as ligands. Full crystallographic information is available from OCA.
Reference
Stability and folding kinetics of structurally characterized cytochrome c-b562., Faraone-Mennella J, Tezcan FA, Gray HB, Winkler JR, Biochemistry. 2006 Sep 5;45(35):10504-11. PMID:16939202
Page seeded by OCA on Wed Nov 21 08:42:57 2007
