Xu M Q, Perler F B
New England Biolabs, Inc., Beverly, MA 01915, USA.
EMBO J. 1996 Oct 1;15(19):5146-53.
Protein splicing results in the expression of two mature proteins from a single gene. After synthesis of a precursor protein, an internal segment (the intein) is excised and the external domains are joined together. A self-catalyzed mechanism for this cleavage-ligation reaction is presented, based on mutagenesis data and analysis of splicing intermediates. Mutations were used to block various steps in the protein splicing pathway, allowing each isolated step to be studied independently. A linear ester intermediate was identified and functional roles for the four conserved splice junction residues were determined. Understanding the mechanism of protein splicing provides a basis for protein engineering studies. For example, inteins can be constructed which fail to splice, but instead cleave the peptide bond at a chosen splice junction.
蛋白质剪接可使单个基因表达出两种成熟蛋白质。在前体蛋白合成后，内部片段（内含肽）被切除，外部结构域连接在一起。基于诱变数据和剪接中间体分析，提出了这种切割-连接反应的自催化机制。通过突变来阻断蛋白质剪接途径中的各个步骤，从而能够独立研究每个分离的步骤。鉴定出一种线性酯中间体，并确定了四个保守剪接连接残基的功能作用。了解蛋白质剪接机制为蛋白质工程研究提供了基础。例如，可以构建无法进行剪接但能在选定剪接连接处切割肽键的内含肽。
