Architectural Features of Human Mitochondrial Cysteine Desulfurase Complexes from Crosslinking Mass Spectrometry and Small-Angle X-Ray Scattering

Structure. 2018 Aug 7;26(8):1127-1136.e4. doi: 10.1016/j.str.2018.05.017. Epub 2018 Jul 5.

Abstract

Cysteine desulfurase plays a central role in mitochondrial iron-sulfur cluster biogenesis by generating sulfur through the conversion of L-cysteine to L-alanine and by serving as the platform for assembling other components of the biosynthetic machinery, including ISCU, frataxin, and ferredoxin. The human mitochondrial cysteine desulfurase complex consists of two copies each of NFS1, ISD11, and acyl carrier protein. We describe results from chemical crosslinking coupled with tandem mass spectrometry and small-angle X-ray scattering studies that are consistent with a closed NFS1 dimer rather than an open one for both the cysteine desulfurase-ISCU and cysteine desulfurase-ISCU-frataxin complexes. We present a structural model for the cysteine desulfurase-ISCU-frataxin complex derived from chemical crosslinking restraints in conjunction with the recent crystal structure of the cysteine desulfurase-ISCU-zinc complex and distance constraints from nuclear magnetic resonance.

Keywords: crosslinking coupled with tandem mass spectrometry (XL-MS); iron-sulfur cluster biosynthesis; small-angle X-ray scattering (SAXS).

Publication types

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

MeSH terms

  • Acyl Carrier Protein / chemistry*
  • Acyl Carrier Protein / genetics
  • Acyl Carrier Protein / metabolism
  • Binding Sites
  • Carbon-Sulfur Lyases / chemistry*
  • Carbon-Sulfur Lyases / genetics
  • Carbon-Sulfur Lyases / metabolism
  • Cloning, Molecular
  • Cross-Linking Reagents / chemistry
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Frataxin
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Humans
  • Iron-Binding Proteins / chemistry*
  • Iron-Binding Proteins / genetics
  • Iron-Binding Proteins / metabolism
  • Iron-Regulatory Proteins / chemistry*
  • Iron-Regulatory Proteins / genetics
  • Iron-Regulatory Proteins / metabolism
  • Iron-Sulfur Proteins / chemistry*
  • Iron-Sulfur Proteins / genetics
  • Iron-Sulfur Proteins / metabolism
  • Kinetics
  • Maleimides / chemistry
  • Mitochondria / chemistry
  • Mitochondria / enzymology
  • Models, Molecular
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Scattering, Small Angle
  • Substrate Specificity
  • Tandem Mass Spectrometry
  • X-Ray Diffraction

Substances

  • Acyl Carrier Protein
  • Cross-Linking Reagents
  • ISCU protein, human
  • Iron-Binding Proteins
  • Iron-Regulatory Proteins
  • Iron-Sulfur Proteins
  • LYRM4 protein, human
  • Maleimides
  • Recombinant Proteins
  • sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate
  • Carbon-Sulfur Lyases
  • NFS1 protein, human
  • cysteine desulfurase