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PROTEINS FROM EIGHT EUKARYOTIC CYTOCHROME P-450 FAMILIES SHARE A SEGMENTED REGION OF SEQUENCE SIMILARITY
Citation:
Kalb, V. AND J. Loper. PROTEINS FROM EIGHT EUKARYOTIC CYTOCHROME P-450 FAMILIES SHARE A SEGMENTED REGION OF SEQUENCE SIMILARITY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/301 (NTIS PB93229235), 1988.
Description:
Proteins from eight eukaryotic families in the cytochrome P-450 superfamily share one region of sequence similarity. his region begins 275-310 amino acids from the amino terminus of each P-450, continues for 170 residues, and ends 35-50 amino acids before the carboxyl terminus. he region can be divided into four domains of sequence similarity, each possessing its own pattern of invariant, conserved, and variable amino acids. he four domains are 56, 20, 59, and 28 residues long and are connected by three shorter segments of limited sequence similarity. he number of residues in these short segments varies with the P-450 protein but ranges from 0 to 20 residues. onsensus sequences based on these similarities can be used to determine whether the sequence of an unidentified peptide resembles that expected for a P-450. equence similarities between proteins sometimes reflect constraints imposed by the requirements of a common function. he fourth domain of the P-450s, for example, contains an invariant cysteine that provides the axial thiolate ligand to the heme iron. ther relationships between the four domains and P-450 function can be examined by in vitro mutagenic procedures that alter the conserved amino acids or modify the distance between domains.
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PROTEINS FROM EIGHT EUKARYOTIC CYTOCHROME P-450 FAMILIES SHARE A SEGMENTED REGION OF SEQUENCE SIMILARITY