Crystal structure of P. falciparum Cpn60 bound to ATP reveals an open dynamic conformation before substrate binding

Sci Rep. 2021 Mar 15;11(1):5930. doi: 10.1038/s41598-021-85197-3.

Abstract

Plasmodium falciparum harbors group 1 and group 2 chaperonin systems to mediate the folding of cellular proteins in different cellular locations. Two distinct group 1 chaperonins operate in the organelles of mitochondria and apicoplasts, while group 2 chaperonins function in the cytosol. No structural information has been reported for any chaperonin from plasmodium. In this study, we describe the crystal structure of a double heptameric ring Plasmodium falciparum mitochondrial chaperonin 60 (Cpn60) bound with ATP, which differs significantly from any known crystal structure of chaperonin 60. The structure likely represents a unique intermediate state during conformational conversion from the closed state to the opened state. Three of the seven apical domains are highly dynamic while the equatorial domains form a stable ring. The structure implies large movements of the apical domain in the solution play a role in nucleotide-dependent regulation of substrate binding and folding. A unique 26-27 residue insertion in the equatorial domain of Plasmodium falciparum mitochondrial chaperonin greatly increases both inter-ring and intra-ring subunit-subunit interactions. The present structure provides new insights into the mechanism of Cpn60 in chaperonin assembly and function.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adenosine Triphosphate / chemistry*
  • Adenosine Triphosphate / metabolism
  • Binding Sites
  • Chaperonin 60 / chemistry*
  • Chaperonin 60 / genetics
  • Chaperonin 60 / metabolism
  • Crystallography, X-Ray
  • Molecular Conformation
  • Molecular Docking Simulation*
  • Molecular Dynamics Simulation*
  • Plasmodium falciparum / metabolism
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protozoan Proteins / chemistry*
  • Protozoan Proteins / metabolism
  • Structure-Activity Relationship

Substances

  • Chaperonin 60
  • Protozoan Proteins
  • Adenosine Triphosphate