The bacterial Mrp ORP is a novel Mrp/NBP35 protein involved in iron-sulfur biogenesis

Sci Rep. 2019 Jan 24;9(1):712. doi: 10.1038/s41598-018-37021-8.


Despite recent advances in understanding the biogenesis of iron-sulfur (Fe-S) proteins, most studies focused on aerobic bacteria as model organisms. Accordingly, multiple players have been proposed to participate in the Fe-S delivery step to apo-target proteins, but critical gaps exist in the knowledge of Fe-S proteins biogenesis in anaerobic organisms. Mrp/NBP35 ATP-binding proteins are a subclass of the soluble P-loop containing nucleoside triphosphate hydrolase superfamily (P-loop NTPase) known to bind and transfer Fe-S clusters in vitro. Here, we report investigations of a novel atypical two-domain Mrp/NBP35 ATP-binding protein named MrpORP associating a P-loop NTPase domain with a dinitrogenase iron-molybdenum cofactor biosynthesis domain (Di-Nase). Characterization of full length MrpORP, as well as of its two domains, showed that both domains bind Fe-S clusters. We provide in vitro evidence that the P-loop NTPase domain of the MrpORP can efficiently transfer its Fe-S cluster to apo-target proteins of the ORange Protein (ORP) complex, suggesting that this novel protein is involved in the maturation of these Fe-S proteins. Last, we showed for the first time, by fluorescence microscopy imaging a polar localization of a Mrp/NBP35 protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AAA Proteins / genetics
  • AAA Proteins / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cytosol
  • Desulfovibrio / classification
  • Desulfovibrio / genetics
  • Desulfovibrio / metabolism*
  • GTP-Binding Proteins / genetics
  • GTP-Binding Proteins / metabolism*
  • Iron / metabolism*
  • Iron-Sulfur Proteins / genetics
  • Iron-Sulfur Proteins / metabolism*
  • Molybdoferredoxin / metabolism
  • Nitrogenase / genetics
  • Nitrogenase / metabolism
  • Protein Binding
  • Protein Domains
  • Sulfur / metabolism*


  • Bacterial Proteins
  • Iron-Sulfur Proteins
  • Molybdoferredoxin
  • Sulfur
  • Iron
  • Nitrogenase
  • GTP-Binding Proteins
  • AAA Proteins