Biomolecular Interaction Centre, University of Canterbury, 8140 Christchurch, New Zealand.
Department of Chemistry, University of Canterbury, 8140 Christchurch, New Zealand.
Proc Natl Acad Sci U S A. 2018 Mar 20;115(12):3006-3011. doi: 10.1073/pnas.1717621115. Epub 2018 Mar 5.
Most proteins comprise two or more domains from a limited suite of protein families. These domains are often rearranged in various combinations through gene fusion events to evolve new protein functions, including the acquisition of protein allostery through the incorporation of regulatory domains. The enzyme 3-deoxy-d--heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of aromatic amino acid biosynthesis and displays a diverse range of allosteric mechanisms. DAH7PSs adopt a common architecture with a shared (β/α) catalytic domain which can be attached to an ACT-like or a chorismate mutase regulatory domain that operates via distinct mechanisms. These respective domains confer allosteric regulation by controlling DAH7PS function in response to ligand Tyr or prephenate. Starting with contemporary DAH7PS proteins, two protein chimeras were created, with interchanged regulatory domains. Both engineered proteins were catalytically active and delivered new functional allostery with switched ligand specificity and allosteric mechanisms delivered by their nonhomologous regulatory domains. This interchangeability of protein domains represents an efficient method not only to engineer allostery in multidomain proteins but to create a new bifunctional enzyme.
大多数蛋白质由来自有限的蛋白质家族套件的两个或更多结构域组成。这些结构域通常通过基因融合事件以各种组合重新排列，以进化新的蛋白质功能，包括通过整合调节结构域获得蛋白质变构调节。3-脱氧-d-赤藓酮 7-磷酸合酶（DAH7PS）是芳香族氨基酸生物合成的第一个酶，表现出多种变构机制。DAH7PS 采用具有共享（β/α）催化结构域的常见架构，该结构域可以连接到 ACT 样或分支酸变位酶调节结构域，它们通过不同的机制发挥作用。这些各自的结构域通过控制 DAH7PS 功能对配体 Tyr 或预苯酸的反应来赋予变构调节。从当代 DAH7PS 蛋白开始，创建了两个具有互换调节结构域的蛋白质嵌合体。这两种工程化蛋白质都是催化活性的，并具有新的功能变构性，其非同源调节结构域提供了改变的配体特异性和变构机制。蛋白质结构域的这种可互换性不仅是工程化多结构域蛋白变构的有效方法，而且是创建新的双功能酶的有效方法。
