Molecules (Nov 2016)

Structures and Ribosomal Interaction of Ribosome-Inactivating Proteins

  • Wei-Wei Shi,
  • Amanda Nga-Sze Mak,
  • Kam-Bo Wong,
  • Pang-Chui Shaw

DOI
https://doi.org/10.3390/molecules21111588
Journal volume & issue
Vol. 21, no. 11
p. 1588

Abstract

Read online

Ribosome-inactivating proteins (RIPs) including ricin, Shiga toxin, and trichosanthin, are RNA N-glycosidases that depurinate a specific adenine residue (A-4324 in rat 28S ribosomal RNA, rRNA) in the conserved α-sarcin/ricin loop (α-SRL) of rRNA. RIPs are grouped into three types according to the number of subunits and the organization of the precursor sequences. RIPs are two-domain proteins, with the active site located in the cleft between the N- and C-terminal domains. It has been found that the basic surface residues of the RIPs promote rapid and specific targeting to the ribosome and a number of RIPs have been shown to interact with the C-terminal regions of the P proteins of the ribosome. At present, the structural basis for the interaction of trichosanthin and ricin-A chain toward P2 peptide is known. This review surveys the structural features of the representative RIPs and discusses how they approach and interact with the ribosome.

Keywords