A conserved motif flags acyl carrier proteins for β-branching in polyketide synthesis.
A conserved motif flags acyl carrier proteins for β-branching in polyketide synthesis.
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DOI：
10.1038/nchembio.1342
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发表时间：
2013-11
影响因子：
14.8
通讯作者：
Crump MP
中科院分区：
文献类型：
--
作者：
Haines AS;Dong X;Song Z;Farmer R;Williams C;Hothersall J;Płoskoń E;Wattana-Amorn P;Stephens ER;Yamada E;Gurney R;Takebayashi Y;Masschelein J;Cox RJ;Lavigne R;Willis CL;Simpson TJ;Crosby J;Winn PJ;Thomas CM;Crump MP
I型PKS通常利用程序化的β-分支，通过“HMG-CoA合酶（HCS）盒”的酶，在来自生长的聚酮骨架的末端羧酸的第二个碳处掺入各种侧链。我们在酰基载体蛋白（ACP）中鉴定了一个强序列基序，其中β-分支是已知的。替换ACP证实ACP类型与β-分支特异性相关。虽然这些ACP通常串联出现，但串联β-分支ACP的NMR分析表明没有ACP-ACP协同效应，并揭示保守序列基序形成内部核心而不是暴露的补丁。建模和诱变鉴定出ACP受阻III作为ACP-HCS复合物的可能锚点，其位置由核心决定。突变核心影响ACP功能，而ACP-HCS界面取代调节系统特异性。我们预测β-碳分支的方法扩展了工程新型聚酮化合物的潜力，并为确定特异性规则奠定了基础。
Type I PKSs often utilise programmed β-branching, via enzymes of an “HMG-CoA synthase (HCS) cassette”, to incorporate various side chains at the second carbon from the terminal carboxylic acid of growing polyketide backbones. We identified a strong sequence motif in Acyl Carrier Proteins (ACPs) where β-branching is known. Substituting ACPs confirmed a correlation of ACP type with β-branching specificity. While these ACPs often occur in tandem, NMR analysis of tandem β-branching ACPs indicated no ACP-ACP synergistic effects and revealed that the conserved sequence motif forms an internal core rather than an exposed patch. Modelling and mutagenesis identified ACP Helix III as a probable anchor point of the ACP-HCS complex whose position is determined by the core. Mutating the core affects ACP functionality while ACP-HCS interface substitutions modulate system specificity. Our method for predicting β-carbon branching expands the potential for engineering novel polyketides and lays a basis for determining specificity rules.