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

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.

Differential protein expression during growth on linear versus branched alkanes in the obligate marine hydrocarbon‐degrading bacterium Alcanivorax borkumensis SK2T

“…RubB expression was greatest during growth on n-C 14, although expression was observed while growing on all three substrates at levels that were not significantly different. alkB1/alkB2 expression is strictly n-alkane dependent, as confirmed here by the expression of AlkB2 only while growing on n-C 14 , but RubA/RubB are constitutively expressed in other bacteria (Geissdörfer et al, 1999;Tani et al, 2001;Marín et al, 2003). The unbalanced expression between monooxygenase (AlkB2) to rubredoxin/rubredoxin reductase (RubA/RubB) suggest that the molecules of membranebound monooxygenases share a limiting number of rubredoxin and rubredoxin reductase molecules, which are soluble proteins that can probably associate and dissociate from the membrane-bound monooxygenase, as seen in P. aeruginosa (Marín et al, 2003).…”

Protein synthesis patterns in Acinetobacter calcoaceticus induced by phenol and catechol show specificities of responses to chemostress

“…The induction of proteins like catalase and alkyl hydroperoxide reductase is regulated in Escherichia coli [16] and many other Gram-negative bacteria by the redox-sensitive transcription factor OxyR, the gene for which has also been detected in Acinetobacter sp. ADP1 [17]. Their induction could indicate the presence of increased concentrations of hydrogen peroxide in cells of A. calcoaceticus treated with catechol, which could be generated via superoxide by redox cycling [18].…”

UV-resistant Acinetobacter sp. isolates from Andean wetlands display high catalase activity

“…With the exception of an ORF homologue to oxyR found in A. baumannii sp. ADP1 (Geissdorfer et al, 1999), which encodes a H 2 O 2 response regulator (Storz et al, 1990), little is known about A.…”