Crystal Structure of Bacillus subtilis Cysteine Desulfurase SufS and Its Dynamic Interaction with Frataxin and Scaffold Protein SufU

PLoS One. 2016 Jul 6;11(7):e0158749. doi: 10.1371/journal.pone.0158749. eCollection 2016.

Abstract

The biosynthesis of iron sulfur (Fe-S) clusters in Bacillus subtilis is mediated by a SUF-type gene cluster, consisting of the cysteine desulfurase SufS, the scaffold protein SufU, and the putative chaperone complex SufB/SufC/SufD. Here, we present the high-resolution crystal structure of the SufS homodimer in its product-bound state (i.e., in complex with pyrodoxal-5'-phosphate, alanine, Cys361-persulfide). By performing hydrogen/deuterium exchange (H/DX) experiments, we characterized the interaction of SufS with SufU and demonstrate that SufU induces an opening of the active site pocket of SufS. Recent data indicate that frataxin could be involved in Fe-S cluster biosynthesis by facilitating iron incorporation. H/DX experiments show that frataxin indeed interacts with the SufS/SufU complex at the active site. Our findings deepen the current understanding of Fe-S cluster biosynthesis, a complex yet essential process, in the model organism B. subtilis.

MeSH terms

  • Alanine / chemistry
  • Alanine / metabolism
  • Bacillus subtilis / enzymology*
  • Bacillus subtilis / genetics
  • Bacillus subtilis / metabolism
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Carbon-Sulfur Lyases / chemistry*
  • Carbon-Sulfur Lyases / genetics
  • Carbon-Sulfur Lyases / metabolism
  • Catalytic Domain
  • Crystallography, X-Ray
  • Cysteine / chemistry
  • Cysteine / metabolism
  • Deuterium Exchange Measurement / methods
  • Frataxin
  • Iron-Binding Proteins / chemistry*
  • Iron-Binding Proteins / metabolism
  • Iron-Sulfur Proteins / chemistry*
  • Iron-Sulfur Proteins / genetics
  • Iron-Sulfur Proteins / metabolism
  • Models, Molecular
  • Multigene Family
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • Pyridoxal Phosphate / chemistry
  • Pyridoxal Phosphate / metabolism
  • Sulfides / chemistry
  • Sulfides / metabolism

Substances

  • Bacterial Proteins
  • Iron-Binding Proteins
  • Iron-Sulfur Proteins
  • Sulfides
  • persulfides
  • Pyridoxal Phosphate
  • Carbon-Sulfur Lyases
  • cysteine desulfurase
  • Cysteine
  • Alanine

Grants and funding

This work was supported by the Deutsche Forschungsgemeinschaft (DFG) by Sonderforschungsbereich 987 (SFB 987) Project B1(http://www.sfb987.de) to MAM, LOEWE excellence initiative of the state of Hesse, Germany (http://www.synmikro.com/en/) to GB and MAM and the Deutsche Forschungsgemeinschaft (DFG) Scientific Instrumentation Grant 160/621-1 FUGG (http://www.dfg.de/en/research_funding/programmes/infrastructure/scientific_instrumentation/equipment_programmes/index.html) to GB and UL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.