The Genes rubA and rubB for Alkane Degradation in Acinetobacter sp. Strain ADP1 Are in an Operon with estB, Encoding an Esterase, andoxyR

ABSTRACT

Alkanes are oxidized in Acinetobacter sp. strain ADP1 by a three-component alkane monooxygenase, composed of alkane hydroxylase, rubredoxin, and rubredoxin reductase. rubA andrubB encode rubredoxin and a NAD(P)H-dependent rubredoxin reductase. We demonstrate here that single base pair substitutions inrubA or rubB lead to defects in alkane degradation, showing that both genes are essential for alkane utilization. Differences in the degradation capacity for hexadecane and dodecane in these mutants are discussed. Two genes, estBand oxyR, are located downstream of rubB, but are not necessary for alkane degradation. estB encodes a functional esterase. oxyR encodes a LysR-type transcriptional regulator, conferring resistance to hydrogen peroxide.rubA, rubB, estB, andoxyR constitute an operon, which is constitutively transcribed from a ς⁷⁰ promoter, and anestB-oxyR containing message is also transcribed from an internal promoter.