Open AccessRegulation of the cyclopropane synthase cfaB gene in Pseudomonas putida KT2440
Author(s) -
Pini Cecilia,
Godoy Patricia,
Bernal Patricia,
Ramos JuanLuis,
Segura Ana
Publication year - 2011
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2011.02317.x
Subject(s) - pseudomonas putida , rpos , mutant , sigma factor , biochemistry , atp synthase , biology , gene , dehydratase , cyclopropane , enzyme , isomerase , chemistry , gene expression , promoter , ring (chemistry) , organic chemistry
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.