Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Biochemistry. 2012 May 8;51(18):3708-10. doi: 10.1021/bi300399u. Epub 2012 Apr 24.
The role of interdomain linkers in modular polyketide synthases is poorly understood. Analysis of the 6-deoxyerythronolide B synthase (DEBS) has yielded a model in which chain elongation is governed by interactions between the acyl carrier protein domain and the ketosynthase domain plus an adjacent linker. Alanine scanning mutagenesis of the conserved residues of this linker in DEBS module 3 led to the identification of the R513A mutant with a markedly reduced rate of chain elongation. Limited proteolysis supported a structural role for this Arg. Our findings highlight the importance of domain-linker interactions in assembly line polyketide biosynthesis.
域间连接物在模块化聚酮合酶中的作用还不太清楚。对 6-脱氧红霉内酯 B 合酶(DEBS)的分析得出了这样一个模型,即链延伸是由酰基载体蛋白结构域与酮合酶结构域和相邻的连接物之间的相互作用来控制的。对 DEBS 模块 3 中这个连接物的保守残基进行丙氨酸扫描诱变,导致鉴定出具有明显降低的链延伸速率的 R513A 突变体。有限的蛋白水解支持这个精氨酸的结构作用。我们的发现强调了在装配线聚酮生物合成中,结构域-连接物相互作用的重要性。