Nonribosomal peptide synthase is responsible for the biosynthesis of siderophore in Vibrio vulnificus MO6-24/O.
Vibrio vulnificus produces siderophores, lowmolecular- weight iron-chelating compounds, to obtain iron under conditions of iron deprivation. To identify genes associated with the biosynthesis of siderophore in V. vulnificus MO6-24/ O, we screened clones with mini-Tn5 random insertions for those showing decreased production of siderophore. Among 6,000 clones screened, nine such clones were selected. These clones contain the transposon inserted in VV2_0830 (GenBank accession number) that is a homolog of a nonribosomal peptide synthetase (NRPS). There is an another NRPS module, VV2_0831, 49-bp upstream to VV2_0830. We named these two genes vvs (Vibrio vulnificus siderophore synthetase) A and B, respectively. Mutation of either vvsA or vvsB showed a decreased production of siderophore. The expression of an NRPS-lux fusion was negatively modulated by the presence of iron, and the regulation was dependent on Fur (ferric uptake regulator). However, the expression of the NRPS genes was still not fully derepressed in the iron-rich condition, even in fur-null mutant cells, suggesting that some other unknown factors are involved in the regulation of the genes. We also demonstrated that the NRPS genes are important for virulence of the pathogen in a mice model.
Kim
In Hwang
IH
Department of Life Science and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul 121-742, Korea.
Shim
Jung-Im
JI
Lee
Ko-Eun
KE
Hwang
Won
W
Kim
Ik-Jung
IJ
Choi
Sang-Ho
SH
Kim
Kun-Soo
KS
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D003360:Cosmids; D003470:Culture Media; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007501:Iron / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010453:Peptide Synthases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017262:Siderophores / Q000096:biosynthesis*; D014735:Vibrio Infections / Q000382:microbiology* / Q000401:mortality; D041261:Vibrio vulnificus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D014774:Virulence
D001426:Bacterial Proteins; D003470:Culture Media; D004251:DNA Transposable Elements; D017262:Siderophores; D007501:Iron; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase