期刊
FEMS MICROBIOLOGY LETTERS
卷 321, 期 2, 页码 107-114出版社
OXFORD UNIV PRESS
DOI: 10.1111/j.1574-6968.2011.02317.x
关键词
cyclopropane synthase; Pseudomonas; cis-trans isomerase
类别
资金
- Ministry of Science and Innovation [BIO2006-05668]
- FEDER [CVI3010]
- CSIC [200440E571]
- BCSH
In Pseudomonas putida, as in many other eubacteria, cyclopropane fatty acids (CFAs) accumulate in the membrane during the stationary phase of growth. Here, we show that cfaB gene expression in P. putida KT2440 is dependent on the RpoS sigma factor that recognizes the sequence 5'-CTACTCT-3' between - 8 and - 14. We have carried out a mutational study of the cfa promoter and have determined that positions - 9, - 12, - 13 and - 14 are the most critical for maximal activity. In P. putida, the substrates of the CFA synthase, cis-unsaturated fatty acids (cis-UFAs), are also substrates for another stress-related enzyme, the cis-trans isomerase (CTI). Despite using the same substrates, we have found that the activity of the CTI is not limited by the CFA synthase activity and vice versa. For instance, in a cfaB knockout mutant, the amount of trans-UFAs synthesized after a specific stress was no higher than in the parental background despite the fact that there are more cis-UFAs available to be used by the CTI as substrates. In this regard, in a cti-deficient mutant background, the levels of CFAs were similar to those in the parental one under the same conditions.
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