Structure of the profilin-poly-L-proline complex involved in morphogenesis and cytoskeletal regulation

Nat Struct Biol. 1997 Nov;4(11):953-60. doi: 10.1038/nsb1197-953.


Profilin, a ubiquitous low molecular weight (13,000-15,000 M(r)) actin binding protein, regulates the formation of F-actin structures in vivo, and is localized to specific cellular regions through interaction with proline-rich sequences. Here we report the 2.2 A X-ray structure of the complex between human platelet profilin (HPP) and a decamer of L-proline (L-Pro10). The L-Pro10 peptide adopts a left-handed type II poly-L-proline helix (PPII) and binds to a highly conserved patch of aromatic amino acids on the surface of profilin. The peptide and actin binding sites reside on orthogonal surfaces, and L-Pro10 binding does not result in a conformational rearrangement of HPP. This structure suggests a mechanism for the localization of profilin and its actin-related activities to sites of actin filament assembly in vivo.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Blood Platelets / chemistry
  • Contractile Proteins*
  • Crystallography, X-Ray
  • Cytoskeleton
  • Humans
  • Ligands
  • Light
  • Microfilament Proteins / chemistry*
  • Microfilament Proteins / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Morphogenesis
  • Oligopeptides / chemistry
  • Peptides / chemistry*
  • Peptides / metabolism
  • Profilins
  • Proline / chemistry
  • Protein Structure, Secondary
  • Scattering, Radiation
  • Sequence Alignment


  • Contractile Proteins
  • Ligands
  • Microfilament Proteins
  • Oligopeptides
  • PFN1 protein, human
  • Peptides
  • Profilins
  • polyproline
  • Proline