cis/trans isomerase of unsaturated fatty acids of Pseudomonas putida P8: evidence for a heme protein of the cytochrome c type.
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.
Holtwick
R
R
Institut für Mikrobiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
Keweloh
H
H
Meinhardt
F
F
D015153:Blotting, Western; D003574:Cytochrome c Group / Q000235:genetics / Q000378:metabolism*; D004251:DNA Transposable Elements; D000431:Ethanol / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D005798:Genes, Bacterial; D006418:Heme / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016297:Mutagenesis, Site-Directed; D009876:Operon; D010957:Plasmids / Q000235:genetics; D016958:Pseudomonas putida / Q000201:enzymology* / Q000235:genetics; D019745:cis-trans-Isomerases / Q000235:genetics / Q000378:metabolism*
D003574:Cytochrome c Group; D004251:DNA Transposable Elements; D005231:Fatty Acids, Unsaturated; D000431:Ethanol; D006418:Heme; D019745:cis-trans-Isomerases