Haslinger Kristina, Redfield Christina, Cryle Max J
Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, Heidelberg, 69120, Germany.
Proteins. 2015 Apr;83(4):711-21. doi: 10.1002/prot.24758. Epub 2015 Feb 5.
The biosynthesis of the glycopeptide antibiotics, of which teicoplanin and vancomycin are representative members, relies on the combination of non-ribosomal peptide synthesis and modification of the peptide by cytochrome P450 (Oxy) enzymes while the peptide remains bound to the peptide synthesis machinery. We have structurally characterized the final peptidyl carrier protein domain of the teicoplanin non-ribosomal peptide synthetase machinery: this domain is believed to mediate the interactions with tailoring Oxy enzymes in addition to its function as a shuttle for intermediates between multiple non-ribosomal peptide synthetase domains. Using solution state NMR, we have determined structures of this PCP domain in two states, the apo and the post-translationally modified holo state, both of which conform to a four-helix bundle assembly. The structures exhibit the same general fold as the majority of known carrier protein structures, in spite of the complex biosynthetic role that PCP domains from the final non-ribosomal peptide synthetase module must play in glycopeptide antibiotic biosynthesis. These structures thus support the hypothesis that it is subtle rearrangements, rather than dramatic conformational changes, which govern carrier protein interactions and selectivity during non-ribosomal peptide synthesis.
糖肽类抗生素的生物合成以替考拉宁和万古霉素为代表成员，其依赖于非核糖体肽合成以及细胞色素P450（Oxy）酶对肽的修饰，而此时肽仍与肽合成机制相连。我们已对替考拉宁非核糖体肽合成酶机制的最终肽基载体蛋白结构域进行了结构表征：除了作为多个非核糖体肽合成酶结构域之间中间体的穿梭功能外，该结构域还被认为介导与修饰性Oxy酶的相互作用。利用溶液态核磁共振技术，我们确定了该肽基载体蛋白结构域在两种状态下的结构，即无辅基状态和翻译后修饰的全酶状态，二者均符合四螺旋束组装结构。尽管来自最终非核糖体肽合成酶模块的肽基载体蛋白结构域在糖肽类抗生素生物合成中必须发挥复杂的生物合成作用，但这些结构与大多数已知载体蛋白结构具有相同的总体折叠方式。因此，这些结构支持了这样一种假说，即在非核糖体肽合成过程中，是细微的重排而非剧烈的构象变化决定了载体蛋白的相互作用和选择性。
