Trypanosoma brucei: functions of RBP16 cold shock and RGG domains in macromolecular interactions

Exp Parasitol. 2003 Oct;105(2):140-8. doi: 10.1016/j.exppara.2003.12.002.

Abstract

The RNA binding protein RBP16 regulates mitochondrial RNA editing and stability in Trypanosoma brucei. To aid in understanding the biochemical mechanisms of RBP16 function, we analyzed the RNA and protein binding capacity of RBP16 and its individual cold shock (CSD) and RGG domains. Both recombinantly expressed domains possess RNA binding activity. However, the specificity and affinity of RBP16 for gRNA is mediated predominantly through the interaction of the CSD with poly(U). The RGG domain contributes to the association between full length RBP16 and gRNA, as it was required for maximal binding. We further demonstrate that both domains contribute to maximal binding of RBP16 to the mitochondrial p22 protein. However, p22 can interact with the CSD alone and stimulate its gRNA binding activity. Thus, the CSD is primary in RBP16 interactions, while the RGG domain enhances the capacity of the CSD to bind both RNA and protein. These results suggest a model for RBP16 molecular interactions.

Publication types

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

MeSH terms

  • Animals
  • Binding, Competitive
  • Chromatography, Affinity
  • Cold Temperature
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme-Linked Immunosorbent Assay
  • Methylation
  • Microspheres
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / metabolism*
  • RNA / metabolism
  • RNA, Guide / metabolism
  • RNA, Mitochondrial
  • RNA, Protozoan / metabolism*
  • RNA-Binding Proteins / chemistry
  • RNA-Binding Proteins / metabolism*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Trypanosoma brucei brucei / genetics
  • Trypanosoma brucei brucei / physiology*

Substances

  • Protozoan Proteins
  • RBP16 protein, Trypanosoma
  • RNA, Guide
  • RNA, Mitochondrial
  • RNA, Protozoan
  • RNA-Binding Proteins
  • Recombinant Proteins
  • RNA