The cysteine desulfhydrase CdsH is conditionally required for sulfur mobilization to the thiamine thiazole in Salmonella enterica

J Bacteriol. 2014 Nov;196(22):3964-70. doi: 10.1128/JB.02159-14. Epub 2014 Sep 2.


Thiamine pyrophosphate is a required coenzyme that contains a mechanistically important sulfur atom. In Salmonella enterica, sulfur is trafficked to both thiamine biosynthesis and 4-thiouridine biosynthesis by the enzyme ThiI using persulfide (R-S-S-H) chemistry. It was previously reported that a thiI mutant strain could grow independent of exogenous thiamine in the presence of cysteine, suggesting there was a second mechanism for sulfur mobilization. Data reported here show that oxidation products of cysteine rescue the growth of a thiI mutant strain by a mechanism that requires the transporter YdjN and the cysteine desulfhydrase CdsH. The data are consistent with a model in which sulfide produced by CdsH reacts with cystine (Cys-S-S-Cys), S-sulfocysteine (Cys-S-SO3 (-)), or another disulfide to form a small-molecule persulfide (R-S-S-H). We suggest that this persulfide replaced ThiI by donating sulfur to the thiamine sulfur carrier protein ThiS. This model describes a potential mechanism used for sulfur trafficking in organisms that lack ThiI but are capable of thiamine biosynthesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cystathionine gamma-Lyase / genetics
  • Cystathionine gamma-Lyase / metabolism*
  • Gene Expression Regulation, Bacterial / physiology*
  • Gene Expression Regulation, Enzymologic / physiology
  • Salmonella enterica / enzymology*
  • Salmonella enterica / genetics
  • Salmonella enterica / metabolism
  • Sulfur / metabolism*
  • Thiamine / biosynthesis*
  • Thiamine / chemistry


  • Sulfur
  • Cystathionine gamma-Lyase
  • Thiamine