A new cytochrome P450 (CYP30) family identified in the clam, Mercenaria mercenaria

A full-length clone with sequence similarity to genes in the cytochrome P450 superfamily was isolated from a cDNA library prepared from female Mercenaria mercenaria gonadal tissue. This clone was isolated while screening an expression library with an antibody prepared against a peptide sequence within the ligand-binding region of the murine Ah receptor. Comparison of the predicted amino acid sequence of this clone to those of other cytochrome P450 genes indicated that the closest overall sequence similarity (38%) was to proteins predicted from genes in the CYP3 family. Northern blots indicated the presence of a transcript of the appropriate size (3.0 kb) with homology to the clam cytochrome P450. In vitro translation of the cDNA clone produced a 50.7-kDa protein as determined by SDS-polyacrylamide gel electrophoresis. The in vitro translated protein was not recognized on Western blots by two polyclonal antibodies specific for members of the CYP3 family. Since the degree of similarity to existing cytochrome P450 families was below the 40% level required for membership, and the expressed protein was not recognized by CYP3-specific antibodies, this clam cytochrome P450 cDNA has been placed in a new family, cytochrome P450 30 (CYP30). (C) 1998 Elsevier Science Inc. All rights reserved.