||Proteins from Eight Eukaryotic Cytochrome P-450 Families Share a Segmented Region of Sequence Similarity.
Kalb, V. F. ;
Loper, J. C. ;
||Cincinnati Univ., OH. Dept. of Microbiological and Molecular Genetics.;Environmental Protection Agency, Cincinnati, OH. Risk Reduction Engineering Lab.
Cytochrome P-450 ;
Amino acid sequence homology ;
Eukaryotic cells ;
Reiterated genes ;
Sequence alignment ;
Saccharomyces cerevisiae ;
Pseudomonas putida ;
Conserved sequence ;
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||Proteins from eight eukaryotic families in the cytochrome P-450 superfamily share one region of sequence similarity. This region begins 275-310 amino acids from the amino terminus of each P-450, continues for about 170 residues, and ends 35-50 amino acids before the carboxyl terminus. The region can be divided into four domains of sequence similarity, each possessing its own pattern of invariant, conserved, and variable amino acids. The four domains are 56, 20, 59, and 28 residues long and are connected by three shorter segments of limited sequence similarity. The number of residues in these short segments varies with the P-450 protein but ranges from 0 to 20 residues. Consensus sequences based on these similarities can be used to determine whether the sequence of an unidentified peptide resembles that expected for a P-450. Sequence similarities between proteins sometimes reflect constraints imposed by the requirements of a common function. The fourth domain of the P-450s, for example, contains an invariant cysteine that provides the axial thiolate ligand to the heme iron. Other 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.
||Pub. in Proceedings for the National Academy of Science, v85 p7221-7225 Oct 88. Sponsored by Environmental Protection Agency, Cincinnati, OH. Risk Reduction Engineering Lab.
|NTIS Title Notes
||Reprint: Proteins from Eight Eukaryotic Cytochrome P-450 Families Share a Segmented Region of Sequence Similarity.
||PC A02/MF A01