Two distinct monooxygenases for alkane oxidation in Nocardioides sp strainCF8

Alkane monooxygenases in Nocardioides sp. strain CF8 were examined at the p hysiological and genetic levels. Strain CF8 can utilize alkanes ranging in chain length from C-2 to C-16. Butane degradation by butane-grown cells was strongly inhibited by allylthiourea, a copper-selective chelator, while he xane-, octane-, and decane-grown cells showed detectable butane degradation activity in the presence of allylthiourea. Growth on butane and hexane was strongly inhibited by 1-hexyne, while 1-hexyne did not affect growth on oc tane or decane. A specific 30-kDa acetylene-binding polypeptide was observe d for butane-, hexane-, octane-, and decane-grown cells but was absent from cells grown with octane or decane in the presence of 1-hexyne. These resul ts suggest the presence of two monooxygenases in strain CF8. Degenerate pri mers designed for PCR amplification of genes related to the binuclear-iron- containing alkane hydroxylase from Pseudomonas oleovorans were used to clon e a related gene from strain CF8. Reverse transcription-PCR and Northern bl ot analysis showed that this gene encoding a binuclear-iron-containing alka ne hydroxylase was expressed in cells grown on alkanes above C-6. These res ults indicate the presence of two distinct monooxygenases for alkane oxidat ion in Nocardioides sp. strain CF8.