TY  - JOUR
A1  - Dahl, Jan-Ulrik
A1  - Radon, Christin
A1  - Bühning, Martin
A1  - Nimtz, Manfred
A1  - Leichert, Lars I.
A1  - Denis, Yann
A1  - Jourlin-Castelli, Cecile
A1  - Iobbi-Nivol, Chantal
A1  - Mejean, Vincent
A1  - Leimkühler, Silke
T1  - The Sulfur Carrier Protein TusA Has a Pleiotropic Role in Escherichia
 coli That Also Affects Molybdenum Cofactor Biosynthesis
JF  - JOURNAL OF BIOLOGICAL CHEMISTRY
N2  - The Escherichia coli L-cysteine desulfurase IscS mobilizes sulfur from L-cysteine for the synthesis of several biomolecules such as iron-sulfur (FeS) clusters, molybdopterin, thiamin, lipoic acid, biotin, and the thiolation of tRNAs. The sulfur transfer from IscS to various biomolecules is mediated by different interaction partners (e.g. TusA for thiomodification of tRNAs, IscU for FeS cluster biogenesis, and ThiI for thiamine biosynthesis/tRNA thiolation), which bind at different sites of IscS. Transcriptomic and proteomic studies of a Delta tusA strain showed that the expression of genes of the moaABCDE operon coding for proteins involved in molybdenum cofactor biosynthesis is increased under aerobic and anaerobic conditions. Additionally, under anaerobic conditions the expression of genes encoding hydrogenase 3 and several molybdoenzymes such as nitrate reductase were also increased. On the contrary, the activity of all molydoenzymes analyzed was significantly reduced in the Delta tusA mutant. Characterization of the Delta tusA strain under aerobic conditions showed an overall low molybdopterin content and an accumulation of cyclic pyranopterin monophosphate. Under anaerobic conditions the activity of nitrate reductase was reduced by only 50%, showing that TusA is not essential for molybdenum cofactor biosynthesis. We present a model in which we propose that the direction of sulfur transfer for each sulfur-containing biomolecule is regulated by the availability of the interaction partner of IscS. We propose that in the absence of TusA, more IscS is available for FeS cluster biosynthesis and that the overproduction of FeS clusters leads to a modified expression of several genes.
Y1  - 2013
U6  - https://doi.org/10.1074/jbc.M112.431569
SN  - 0021-9258
VL  - 288
IS  - 8
SP  - 5426
EP  - 5442
PB  - AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
CY  - BETHESDA
ER  -