4leu

Publication Abstract from PubMed

Pentatricopeptide repeat (PPR) proteins are sequence-specific RNA binding proteins, which form a pervasive family of proteins conserved in yeast, plants, and humans. The plant PPR proteins are mainly grouped into P and PLS classes. Here we report the crystal structure of a PLS-class PPR protein from Arabidopsis thaliana, termed THA8-like (THA8L) at 2.0 A. THA8L resembles the thylakoid assembly 8 (THA8), a protein that is required for the splicing of specific group II introns of genes involved in biogenesis of chloroplast thylakoid membranes. The THA8L structure contains three P-type PPR motifs flanked by one L-type motif and one S-type motif. We identified several putative THA8L-binding sites, enriched with purine sequences, in the group II introns. Importantly, THA8L has strong preferential binding for single stranded RNA over single stranded DNA or double stranded RNA. Structural analysis reveals that THA8L contains two extensive patches of positively charged residues next to the residues that are proposed to comprise the RNA-binding codes. Mutations in these two positively charged patches greatly reduced THA8L RNA-binding activity. Based on these data, we constructed a model of THA8L-RNA binding that is dependent on two forces: one is the interaction between nucleotide bases and specific amino acids in the PPR motifs (codes) and the other is the interaction between negatively charged RNA backbone and positively charged residues of PPR motifs. Together, these results further our understanding of the mechanism of PPR protein-RNA interactions.

Structure of a PLS-Class Pentatricopeptide Repeat Protein Provides Insights into Mechanism of RNA Recognition.,Ban T, Ke J, Chen R, Gu X, Tan MH, Zhou XE, Kang Y, Melcher K, Zhu JK, Xu HE J Biol Chem. 2013 Sep 18. PMID:24047899^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.