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Clarke, Thomas A. 
ORCID: https://orcid.org/0000-0002-6234-1914, Im, Sang-Choul, Bidwai, Anil and Waskell, Lucy
(2004)
The role of the length and sequence of the linker domain of cytochrome b5 in stimulating cytochrome P450 2B4 catalysis.
Journal of Biological Chemistry, 279 (35).
pp. 36809-36818.
ISSN 0021-9258
Abstract
Cytochrome b(5) (cyt b(5)) is a 15-kDa amphipathic protein with a cytosolic amino-terminal catalytic heme domain, which is anchored to the microsomal membrane by a hydrophobic transmembrane alpha-helix at its carboxyl terminus. These two domains are connected by an approximately 15-amino acid linker domain, Ser(90)-Asp(104), which has been modified by site-directed mutagenesis to investigate whether the length or sequence of the linker influences the ability of cyt b(5) to bind ferric cytochrome P450 2B4 and donate an electron to oxyferrous (cyt P450 2B4), thereby stimulating catalysis. Because shortening the linker by 8 or more amino acids markedly inhibited the ability of cyt b(5) to bind cyt P450 2B4 and stimulate catalysis by this isozyme, it is postulated 7 amino acids are sufficient to allow a productive interaction. All mutant cyts b(5) except the protein lacking the entire 15-amino acid linker inserted normally into the microsomal membrane. Alternatively, lengthening the linker by 16 amino acids, reversing the sequence of the amino acids in the linker, and mutating conserved linker residues did not significantly alter the ability of cyt b(5) to interact with cyt P450 2B4. A model for the membrane-bound cyt b(5)-cyt P450 complex is presented.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Biological Sciences |
| UEA Research Groups: | Faculty of Science > Research Groups > Molecular Microbiology Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry Faculty of Science > Research Groups > Energy Materials Laboratory |
| Related URLs: | |
| Depositing User: | Users 2731 not found. |
| Date Deposited: | 24 May 2011 10:19 |
| Last Modified: | 17 Jan 2024 01:23 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/31293 |
| DOI: | 10.1074/jbc.M406055200 |
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