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An extremely SAD case: structure of a putative redox-enzyme maturation protein from Archaeoglobus fulgidus at 3.4 A

Olga Kirillova1, Maksymilian Chruszcz, Igor A Shumilin

  • 1Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA.

Acta Crystallographica. Section D, Biological Crystallography
|March 1, 2007
PubMed

Insights

This study reveals the crystal structure of AF0173, a redox-enzyme maturation protein (REMP) from Archaeoglobus fulgidus. This structure clarifies how REMPs bind twin-arginine motifs, crucial for protein maturation in archaea and bacteria.

Area of Science:

  • Structural biology
  • Biochemistry
  • Microbiology

Background:

  • Redox-enzyme maturation proteins (REMPs) are essential chaperones for extracytoplasmic oxidoreductases in archaea and bacteria.
  • Understanding REMP function is key to deciphering protein maturation pathways in diverse microorganisms.

Purpose of the Study:

  • To determine the crystal structure of AF0173, a putative REMP from Archaeoglobus fulgidus.
  • To elucidate the mechanism by which REMPs interact with twin-arginine motifs.

Main Methods:

  • X-ray crystallography
  • Single anomalous dispersion (SAD) method for structure determination
  • Analysis of protein-protein interactions and conserved residues

Main Results:

  • The crystal structure of AF0173 was solved at 3.4 Å resolution, revealing an all-helical dimeric structure.
  • A funnel-shaped cavity on the subunit surface was identified as a likely binding site for the twin-arginine motif.
  • Structural conservation between archaeal (AF0173) and bacterial REMPs suggests a conserved binding mechanism.

Conclusions:

  • AF0173 structure provides insights into REMP-mediated protein maturation in archaea.
  • The findings suggest a conserved mechanism for twin-arginine motif binding across archaea and bacteria.
  • The study highlights the utility of SAD phasing even in challenging crystallographic cases (low resolution, high solvent content).

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