Regiospecific effect of 1-octanol on cis-trans isomerization of unsaturated fatty acids in the solvent-tolerant strain Pseudomonas putida S12.
The solvent-tolerant bacterium Pseudomonas putida S12, which adapts its membrane lipids to the presence of toxic solvents by a cis to trans isomerization of unsaturated fatty acids, was used to study possible in vivo regiospecificity of the isomerase. Cells were supplemented with linoleic acid (C18:2delta9-cis,delta12-cis), a fatty acid that cannot be synthesized by this bacterium, but which was incorporated into membrane lipids up to an amount of 15% of total fatty acids. After addition of 1-octanol, which was used as an activator of the cis-trans isomerase, the linoleic acid was converted into the delta9-trans,delta12-cis isomer, while the delta9-cis,delta12-trans and delta9-trans,epsilon12-trans isomers were not synthesized. Thus, for the first time, regiospecific in vivo formation of novel, mixed cis/trans isomers of dienoic fatty acid chains was observed. The maximal conversion (27-36% of the chains) was obtained at 0.03-0.04% (v/v) octanol, after 2 h. The observed regiospecificity of the enzyme, which is located in the periplasmic space, could be due to penetration of the enzyme to a specific depth in the membrane as well as to specific molecular recognition of the substrate molecules.
Heipieper
H J
HJ
Department of Bioconversion, ATO, Wageningen UR, The Netherlands. heipiep@san.ufz.de
de Waard
P
P
van der Meer
P
P
Killian
J A
JA
Isken
S
S
de Bont
J A
JA
Eggink
G
G
de Wolf
F A
FA
D020003:1-Octanol / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D016958:Pseudomonas putida / Q000378:metabolism*; D012997:Solvents; D013237:Stereoisomerism; D019745:cis-trans-Isomerases / Q000378:metabolism*
D005231:Fatty Acids, Unsaturated; D008563:Membrane Lipids; D012997:Solvents; D019745:cis-trans-Isomerases; D020003:1-Octanol