cDNA and Protein Sequence of a Major Form of P450, CYP2L, in the Hepatopancreas of the Spiny Lobster,Panulirus argus

A P450 fraction was previously isolated from spiny lobster hepatopancreas microsomes and shown in reconstitution experiments to be efficient in catalyzing the monooxygenation of benzphetamine, aminopyrine, benzo(a)pyrene, progesterone, and testosterone. In this study, N-terminal sequence information up to residue 39 was obtained from this P450 and used to design degenerate primers for screening a cDNA library constructed from hepatopancreas mRNA. Clones were obtained that contained part of the coding region of a P450 protein. Further exact primers were designed that permitted the isolation of clones containing coding information for other parts of the P450 sequence, as well as a clone that coded for the complete P450 protein sequence. The open reading frame of the complete coding region corresponded to a protein of 492 amino acids. The deduced amino acid sequence of this P450 was about 36% similar to individual mammalian P450s in the 2 family and did not show strong matches with other proteins in the data base. Based on sequence and the previously determined function, this spiny lobster P450 was assigned by the P450 nomenclature committee to a new P450 subfamily, CYP2L. This is the first description of a P450 primary sequence from a marine crustacean species and the first assignment of an invertebrate P450 into the 2 family.