Molecular mechanism of constitutively active Rab11A was revealed by crystal structure of Rab11A S20V

FEBS Lett. 2016 Mar;590(6):819-27. doi: 10.1002/1873-3468.12100. Epub 2016 Mar 1.

Abstract

Rab11A is a small GTP-binding protein involved in the regulation of vesicle trafficking during recycling of endosomes. Substitution of S20 to V (S20V) at Rab11A inhibits the GTP hydrolysis activity of Rab11A. This mutation is known to be constitutively in an active form. Here, we report the crystal structure of the human Rab11A S20V mutant form complexed with GTP at a resolution of 2.4 Å. Without adding any substrate, Rab11A contained non-hydrolyzed natural substrate GTP in the nucleotide binding pocket with Mg(2+). In our observations, substituted V20 of Rab11A was found to interfere with proper localization of the water molecule, which mediated GTP hydrolysis, resulting in GTP being locked in an active form of Rab11A S20V.

Keywords: Rab11; crystal structure; membrane trafficking; small G protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Catalytic Domain / genetics
  • Crystallography, X-Ray
  • Enzyme Activation
  • Guanine Nucleotides / metabolism
  • Guanosine Triphosphate / metabolism
  • Humans
  • Hydrolysis
  • Magnesium / metabolism
  • Models, Molecular
  • Molecular Weight
  • Mutagenesis, Site-Directed
  • Protein Conformation
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Water / metabolism
  • rab GTP-Binding Proteins / chemistry*
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism*

Substances

  • Guanine Nucleotides
  • Recombinant Proteins
  • Water
  • Guanosine Triphosphate
  • rab11 protein
  • rab GTP-Binding Proteins
  • Magnesium