TY - JOUR
T1 - Analysis of the exochelin locus in Mycobacterium smegmatis
T2 - Biosynthesis genes have homology with genes of the peptide synthetase family
AU - Yu, Shengwei
AU - Fiss, Ellen
AU - Jacobs, William R.
PY - 1998/9
Y1 - 1998/9
N2 - Mycobacteria secrete the siderophore exochelin when grown under iron- limiting conditions. In order to understand iron uptake mechanisms in mycobacteria, we have taken a genetic approach to identify those genes involved in exochelin biosynthesis and transport in Mycobacterium smegmatis. Of the 6,000 chemically mutagenized clones of M. smegmatis mc2155 screened on agar plates containing chrome azural S, 19 mutants that had lost the ability to produce or secrete exochelin were identified. Thirteen of these mutants were complemented by a single M. smegmatis cosmid. Sequence analysis of this cosmid revealed nine open reading frames, three of which are homologous to genes encoding transporter proteins, which are likely involved in exochelin transport. Complementation and Tn10 mutagenesis analysis identified two new genes, fxbB and fxbC, which are required for exochelin biosynthesis. The fxbB and fxbC genes encode large proteins of 257 and 497 kDa, respectively, which are highly homologous to peptide synthetases, indicating that exochelin biosynthesis occurs by a nonribosomal mechanism.
AB - Mycobacteria secrete the siderophore exochelin when grown under iron- limiting conditions. In order to understand iron uptake mechanisms in mycobacteria, we have taken a genetic approach to identify those genes involved in exochelin biosynthesis and transport in Mycobacterium smegmatis. Of the 6,000 chemically mutagenized clones of M. smegmatis mc2155 screened on agar plates containing chrome azural S, 19 mutants that had lost the ability to produce or secrete exochelin were identified. Thirteen of these mutants were complemented by a single M. smegmatis cosmid. Sequence analysis of this cosmid revealed nine open reading frames, three of which are homologous to genes encoding transporter proteins, which are likely involved in exochelin transport. Complementation and Tn10 mutagenesis analysis identified two new genes, fxbB and fxbC, which are required for exochelin biosynthesis. The fxbB and fxbC genes encode large proteins of 257 and 497 kDa, respectively, which are highly homologous to peptide synthetases, indicating that exochelin biosynthesis occurs by a nonribosomal mechanism.
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U2 - 10.1128/jb.180.17.4676-4685.1998
DO - 10.1128/jb.180.17.4676-4685.1998
M3 - Article
C2 - 9721311
AN - SCOPUS:0031783529
SN - 0021-9193
VL - 180
SP - 4676
EP - 4685
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 17
ER -