Open AccessThe csbX gene of Azotobacter vinelandii encodes an MFS efflux pump required for catecholate siderophore export 1
Author(s) -
Page William J.,
Kwon Elena,
Cornish Anthony S.,
Tindale Anne E.
Publication year - 2003
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 - 10.1016/s0378-1097(03)00753-5
Subject(s) - azotobacter vinelandii , siderophore , operon , efflux , major facilitator superfamily , biosynthesis , mutant , biochemistry , biology , gene , enterobactin , microbiology and biotechnology , atp binding cassette transporter , chemistry , bacteria , transporter , genetics , nitrogenase , nitrogen fixation
The csbX gene of Azotobacter vinelandii was regulated in an iron‐repressible manner from a divergent promoter upstream of the catecholate siderophore biosynthesis ( csb ) operon and was predicted to encode an efflux pump of the major facilitator superfamily. Other proteins that were most similar to CsbX were encoded by genes found in the catecholate siderophore biosynthesis operons of Aeromonas hydrophila and Stigmatella aurantiaca . Inactivation of csbX resulted in 57–100% decrease in the amount of catecholates released when compared to the wild‐type in iron‐limited medium. CsbX was most important for the export of the high affinity chelator protochelin with the majority of the catecholates released by csbX mutants being the protochelin intermediates azotochelin and aminochelin.