Molecular cloning and expression of fatty acid alpha-hydroxylase from Sphingomonas paucimobilis.

Fatty acid alpha-hydroxylase (FAAH) catalyzes the initial reaction in alpha-oxidation of fatty acid to produce 2-hydroxy fatty acid. FAAH activity has been detected in a wide range of organisms from prokaryotes to eukaryotes. Here, we describe cloning of the FAAH gene from Sphingomonas paucimobilis, a sphingolipid- and 2-hydroxymyristic acid-rich bacterium. The isolated gene encoded 415 amino acids. A homology search revealed that amino acid sequences highly conserved in cytochrome P450 (P450) were present in FAAH. Although the heme-binding cysteine was recognizable at position 361, the consensus in the heme-binding region was modified by an insertion. Overall, FAAH has no significant identity to the known P450s. CO difference spectrum of recombinant FAAH showed the characteristic one of P450, except this peak was at 445 nm. These results suggest bacterial FAAH is a novel member of the P450 superfamily.