The Structural Basis of Transit Peptide Interaction(s) with the Chloroplast Toc Receptors

转运肽与叶绿体 Toc 受体相互作用的结构基础

• 批准号: 0344601
• 负责人: Barry Bruce
• 金额: --
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-15 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0344601&HistoricalAwards=false
• 关键词: Structural; Basis; Transit; Peptide; Interaction

Plastids have evolved into semi-autonomous organelles whose metabolic function is heavily dependent upon the import of nuclear-encoded proteins that were initially encoded by ancestral cyanobacterial genomes. The majority of nuclear-encoded proteins that function within the plastid are synthesized as higher molecular weight precursors with an N-terminal extension known as a transit peptide, which mediates specific and efficient targeting of the precursor to plastids. Analysis of the Arabidopsis genome predicts that more than 3000 precursors are plastid-targeted. The structural and functional criteria that define these thousands of transit peptides are not well understood. Analysis of hundreds of transit peptides to date has failed to reveal significant conserved primary sequence, suggesting that a common secondary or tertiary structure may account for the specific targeting activity of transit peptides. In this study, site-directed molecular mutagenesis, NMR, isothermal titration calorimetry, and analytical ultracentrifugation will be used to directly determine the structural basis of peptide-receptor interactions in Arabidopsis. This project will provide a new level of mechanistic understanding of chloroplast protein import. Findings from the project will provide a starting point for additional structure/function analysis of other transit peptides and their interaction with other components of the chloroplast translocation apparatus. An applied aspect of this research may be the enhanced targeting of novel plastid precursor proteins to plastids, thereby improving both the utility and safety of many different agronomic plants and plant products.

质体已经进化成半自主的细胞器，其代谢功能在很大程度上依赖于最初由祖先蓝藻基因组编码的核编码蛋白的输入。 在质体内发挥功能的大多数核编码蛋白质合成为具有称为转运肽的N-末端延伸的较高分子量前体，其介导前体特异性和有效靶向质体。 拟南芥基因组的分析预测，超过3000个前体是质体靶向的。 定义这数千种转运肽的结构和功能标准还不清楚。 迄今为止，对数百种转运肽的分析未能揭示出显著保守的一级序列，这表明共同的二级或三级结构可能是转运肽的特异性靶向活性的原因。 在这项研究中，定点分子突变、核磁共振、等温滴定量热法和分析超速离心将用于直接确定拟南芥中肽与受体相互作用的结构基础。 该项目将提供一个新的水平的叶绿体蛋白质输入机制的理解。 该项目的发现将为其他转运肽及其与叶绿体易位装置其他组分的相互作用的额外结构/功能分析提供起点。 这项研究的一个应用方面可能是增强新型质体前体蛋白对质体的靶向，从而提高许多不同农艺植物和植物产品的实用性和安全性。