Multimodal Spectroscopic Analysis of the Fe-S Clusters of the as-Isolated Escherichia coli SufBC2D Complex

Inorg Chem. 2024 May 13;63(19):8730-8738. doi: 10.1021/acs.inorgchem.4c00304. Epub 2024 Apr 30.

Abstract

Iron-sulfur (Fe-S) clusters are essential inorganic cofactors dedicated to a wide range of biological functions, including electron transfer and catalysis. Specialized multiprotein machineries present in all types of organisms support their biosynthesis. These machineries encompass a scaffold protein, on which Fe-S clusters are assembled before being transferred to cellular targets. Here, we describe the first characterization of the native Fe-S cluster of the anaerobically purified SufBC2D scaffold from Escherichia coli by XAS and Mössbauer, UV-visible absorption, and EPR spectroscopies. Interestingly, we propose that SufBC2D harbors two iron-sulfur-containing species, a [2Fe-2S] cluster and an as-yet unidentified species. Mutagenesis and biochemistry were used to propose amino acid ligands for the [2Fe-2S] cluster, supporting the hypothesis that both SufB and SufD are involved in the Fe-S cluster ligation. The [2Fe-2S] cluster can be transferred to ferredoxin in agreement with the SufBC2D scaffold function. These results are discussed in the context of Fe-S cluster biogenesis.

MeSH terms

  • Carrier Proteins
  • Electron Spin Resonance Spectroscopy
  • Escherichia coli Proteins* / chemistry
  • Escherichia coli Proteins* / metabolism
  • Escherichia coli* / metabolism
  • Iron-Sulfur Proteins* / chemistry
  • Iron-Sulfur Proteins* / metabolism
  • Spectroscopy, Mossbauer
  • X-Ray Absorption Spectroscopy

Substances

  • Iron-Sulfur Proteins
  • Escherichia coli Proteins
  • SufB protein, E coli
  • SufD protein, E coli
  • Carrier Proteins