CYP116B5 : a new class VII catalytically self‐sufficient cytochrome P 450 from A cinetobacter radioresistens that enables growth on alkanes

• Published in: Molecular microbiology Vol. 95; no. 3; pp. 539 - 554
• Main Authors: Minerdi, Daniela, Sadeghi, Sheila J., Di Nardo, Giovanna, Rua, Francesco, Castrignanò, Silvia, Allegra, Paola, Gilardi, Gianfranco
• Format: Journal Article
• Language: English
• Published: 01.02.2015
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.12883

Summary A gene coding for a class VII cytochrome P 450 monooxygenase ( CYP116B5 ) was identified from A cinetobacter radioresistens S13 growing on media with medium ( C 14, C 16) and long ( C 24, C 36) chain alkanes as the sole energy source. Phylogenetic analysis of its N ‐ and C ‐terminal domains suggests an evolutionary model involving a plasmid‐mediated horizontal gene transfer from the donor R hodococcus jostii   RHA1 to the receiving A . radioresistens   S 13. This event was followed by fusion and integration of the new gene in A . radioresistens chromosome. Heterologous expression of CYP116B5 in E scherichia coli   BL 21, together with the A . radioresistens   B aeyer– V illiger monooxygenase, allowed the recombinant bacteria to grow on long‐ and medium‐chain alkanes, showing that CYP116B5 is involved in the first step of terminal oxidation of medium‐chain alkanes overlapping AlkB and in the first step of sub‐terminal oxidation of long‐chain alkanes. It was also demonstrated that CYP116B5 is a self‐sufficient cytochrome P 450 consisting of a heme domain (aa 1–392) involved in the oxidation step of n‐ alkanes degradation, and its reductase domain (aa 444–758) comprising the NADPH ‐, FMN ‐ and [ 2Fe2S ]‐binding sites. To our knowledge, CYP116B5 is the first member of this class to have its natural substrate and function identified.