Identification and Characterization of 9-cis-Hexadecenoic Acid Cis-Trans Isomerase of Pseudomonas Sp. Strain E-3

Abstract

Some bacterial cells contain mono-unsaturated fatty acids with a trans-confuguration as acyl components of membrane phospholipids. We found the temperature-dependent alteration in levels of a trans-mono-unsaturated fatty acid, 16:1(9t), in a psychrophilic bacterium, Vibrio sp. strain ABE-1 [1]. Morita et al. [2] presented the evidence for the direct in vivo isomerization between 16:1(9c) and 16:1(9t) in cells of this bacterium using stable isotope tracers, namely, [2,2-²H₂]16:1(9c) and [2,2-²H₂]16:1(9t). This isomerization is quite unique because of configurational isomerization of a double bond without shifting of the double bond position. In this article, we decribe purification and characterization of cis-trans isomerase from a psychrotrophic bacterium, Pseudomonas sp. strain E-3 (Pseudomonas E-3), another organism that contains 16:1(9t) [1], and the possible physiological roles of trans-mono-unsaturated fatty acid in this bacterium.