Systematic analysis on RNA recognition mechanism of PPR protein for plant organelle gene expression

五肽重复（PPR）蛋白是真核生物中常见的rna结合蛋白。细胞器转录加工和稳定性由PPR蛋白以基因特异性的方式介导，通过串联阵列识别退化的35个氨基酸重复单元（PPR基序）。在这里，我们展示了参与RNA编辑的PPR蛋白的RNA识别原理。基序内3个特定位置的氨基酸变化以可编程的方式决定了对特定RNA的识别，具有1-基序与1-核苷酸的对应关系。这3种氨基酸的解码核苷酸频率数据被用于为几种PPR蛋白分配精确的相互作用位点进行RNA编辑，并预测未表征的PPR蛋白的靶位点。从另一个角度来看，PPR蛋白似乎提供了一个极有希望的机会来创造具有定制特异性的定制RNA结合蛋白。

Pentatricopeptide repeat (PPR) proteins are eukaryotic RNA-binding proteins that are commonly found in plants. Organelle transcript processing and stability are mediated by PPR proteins in a gene-specific manner through recognition by tandem arrays of degenerate 35-amino-acid repeating units, the PPR motifs. Here, we showed the principle underlying RNA recognition for PPR proteins involved in RNA editing. Amino acid variation at 3 particular positions within the motif determined recognition of a specific RNA in a programmable manner, with a 1-motif to 1-nucleotide correspondence,. Data from the decoded nucleotide frequencies for these 3 amino acids were used to assign accurate interacting sites to several PPR proteins for RNA editing and to predict the target sites for an uncharacterized PPR proteins. In another view, PPR proteins appear to provide an extremely promising opportunity to create custom RNA binding proteins with tailored specificity.