Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
Trends Plant Sci. 2013 Jul;18(7):360-6. doi: 10.1016/j.tplants.2013.04.003. Epub 2013 May 18.
Import of most nuclear encoded proteins into plastids is directed by an N-terminal transit peptide. Early studies suggested that transit peptides are interchangeable between precursor proteins. However, emerging evidence shows that different transit peptides contain different motifs specifying their preference for certain plastid types or ages. In this opinion article, we propose a 'multi-selection and multi-order' (M&M) model for transit peptide design, describing each transit peptide as an assembly of motifs for interacting with selected translocon components. These interactions determine the preference of the precursor for a particular plastid type or age. Furthermore, the order of the motifs varies among transit peptides, explaining why no consensus sequences have been identified through linear sequence comparison of all transit peptides as one group.
大多数核编码蛋白向质体的输入是由 N 端转运肽指导的。早期的研究表明，转运肽在前体蛋白之间是可互换的。然而，新出现的证据表明，不同的转运肽包含不同的基序，指定它们对某些质体类型或年龄的偏好。在这篇观点文章中，我们提出了一个转运肽设计的“多选择和多顺序”（M&M）模型，将每个转运肽描述为与选定的易位子组件相互作用的基序的集合。这些相互作用决定了前体蛋白对特定质体类型或年龄的偏好。此外，在转运肽中，基序的顺序是不同的，这解释了为什么通过对所有转运肽作为一个整体进行线性序列比较，没有确定出一致的序列。
