cis/trans Isomerase of Unsaturated Fatty Acids of Pseudomonas putida P8: Evidence for a Heme Protein of the Cytochrome c Type†

AUTOR(ES)
FONTE

American Society for Microbiology

RESUMO

From a pool of 600 temperature-sensitive transposon mutants of Pseudomonas putida P8, 1 strain was isolated that carries a mini-Tn5 insertion within the cytochrome c operon. As a result, genes involved in the attachment of heme to cytochrome c-type proteins are turned off. Accordingly, cytochrome c could not be detected spectrophotometrically. The mutant also exhibited a remarkable reduction of cis-trans isomerization capability for unsaturated fatty acids. Consistent with the genetic and physiological data is the detection of a cytochrome c-type heme-binding motif close to the N terminus of the predicted polypeptide of the cis/trans isomerase (cti) gene (CVACH; conserved amino acids in italics). The functional significance of this motif was proven by site-directed mutagenesis. A possible mechanism of heme-catalyzed cis-trans isomerization of unsaturated fatty acids is discussed.

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