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The regulation of the cis‐trans isomerase of unsaturated fatty acids in Pseudomonas putida : correlation between cti activity and K + ‐uptake systems
Author(s) -
Neumann Grit,
Kabelitz Nadja,
Heipieper Hermann J.
Publication year - 2003
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.200300803
Subject(s) - pseudomonas putida , osmotic shock , chemistry , isomerase , substrate (aquarium) , membrane fluidity , membrane , isomerization , enzyme , double bond , biochemistry , biophysics , organic chemistry , catalysis , biology , ecology , gene
The regulation of an urgent stress adaptive mechanism of Pseudomonas putida , the isomerization of cis ‐ to trans ‐unsaturated fatty acids, was investigated. By comparing the responses of the cells to a series of stress factors, a direct correlation between the activation of this unique mechanism and the well‐investigated K + ‐uptake pumps was observed. Only those stress conditions (osmotic stress caused by glycerol, cold shock, high pH) that are well known not to activate cellular K + ‐uptake, showed no effect on the cis‐trans isomerase (cti). On the other hand, organic solvents, osmotic stress caused by NaCl and sucrose, heavy metals, heat shock and membrane‐active antibiotics activated both K + ‐uptake and the cti system. This seems to be another indication for an activation of the constitutively present cti by increasing membrane fluidity. The enzyme, which is located in the periplasma, can only reach its substrate, the double bond in the hydrophobic zone of the membrane bilayer, when the membrane fluidity is disturbed by an environmental factor.