Folding energy landscape of cytochrome cb562.

ABSTRACT: Cytochrome cb(562) is a variant of an Escherichia coli four-helix bundle b-type heme protein in which the porphyrin prosthetic group is covalently ligated to the polypeptide near the terminus of helix 4. Studies from other laboratories have shown that the apoprotein folds rapidly without the formation of intermediates, whereas the holoprotein loses heme before native structure can be attained. Time-resolved fluorescence energy transfer (TRFET) measurements of cytochrome cb(562) refolding triggered using an ultrafast continuous-flow mixer (150 micros dead time) reveal that heme attachment to the polypeptide does not interfere with rapid formation of the native structure. Analyses of the TRFET data produce distributions of Trp-59-heme distances in the protein before, during, and after refold

SUBMITTER: Kimura T 

PROVIDER: S-EPMC2683080 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature