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

五肽重复序列（PPR）蛋白是一类常见于植物中的真核RNA结合蛋白。细胞器转录物的加工和稳定性是由PPR蛋白以基因特异性的方式介导的，通过由简并的35个氨基酸重复单元（PPR基序）的串联阵列识别。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个特定位置处的氨基酸变异以可编程方式确定特异性RNA的识别，其中1-基序与1-核苷酸对应。来自这3个氨基酸的解码核苷酸频率的数据用于将准确的相互作用位点分配给用于RNA编辑的几种PPR蛋白，并预测未表征的PPR蛋白的靶位点。在另一种观点中，PPR蛋白似乎提供了一个非常有希望的机会来创建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.