Assessing the integrity of designed homomeric parallel three-stranded coiled coils in the presence of metal ions
Assessing the integrity of designed homomeric parallel three-stranded coiled coils in the presence of metal ions
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DOI：
10.1021/ic061183e
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发表时间：
2006-12-11
影响因子：
4.6
通讯作者：
Pecoraro, Vincent L.
中科院分区：
文献类型：
--
作者：
Iranzo, Olga;Ghosh, Debdip;Pecoraro, Vincent L.
自组装形成螺旋卷曲螺旋的α-螺旋肽的从头设计是研究肽/蛋白质之间的分子识别和确定其折叠和结构中涉及的基本力的有力工具。这些两亲性螺旋在水溶液中组装以产生最终的卷曲螺旋基序，其中疏水残基在内部，极性/亲水基团在外部。已经投入了相当大的努力来研究确定盘绕弹簧圈的整体稳定性和最终三维结构的力。卷曲螺旋设计中的主要挑战之一是在寡聚体状态方面实现特异性，关于数量（2、3、4或更高）、性质（同聚体vs异聚体）和链取向（平行vs反平行）。在自然界中，金属离子在这种自组织过程中起着重要作用，金属蛋白的整体结构主要是两种驱动力的结果：金属配位偏好和多肽骨架的折叠。我们小组先前的工作表明，金属离子如As（III）和Hg（II）可用于在设计的同源三聚体卷曲螺旋TRI家族[Ac-G（LKALEEK）（4）G-CONH 2]的Cys衍生物中增强不同的聚集状态。我们现在有兴趣研究金属离子和肽偏好之间的相互作用，以控制卷曲螺旋中α-螺旋的特异性和相对取向。为了这个目的，已经合成了TRI家族的两种衍生物，TRi L2 WL 9 C和TRi L2 WL 23 C。沿着这两种肽，还使用了卷曲-Ser的两种衍生物，CSL 9 C和CSL 19 C（CS）Ac-EWEALEKKLAALESKLQALEKKLEALEHG-CONH 2），一种类似的从头设计的三链卷曲螺旋，其具有形成反平行卷曲螺旋的潜力。圆二色性，紫外-可见，和Hg-199和Cd-113 NMR光谱的结果表明，除了Hg（II）和Cd（II）的这些肽的不同混合物的形式优先homotrimeric卷曲螺旋，在一个统计人口的heterotrimeric平行和antiparallel卷曲螺旋。
De novo design of alpha-helical peptides that self-assemble to form helical coiled coils is a powerful tool for studying molecular recognition between peptides/proteins and determining the fundamental forces involved in their folding and structure. These amphipathic helices assemble in aqueous solution to generate the final coiled coil motif, with the hydrophobic residues in the interior and the polar/hydrophilic groups on the exterior. Considerable effort has been devoted to investigate the forces that determine the overall stability and final three-dimensional structure of the coiled coils. One of the major challenges in coiled coil design is the achievement of specificity in terms of the oligomeric state, with respect to number (two, three, four, or higher), nature (homomers vs heteromers), and strand orientation (parallel vs antiparallel). As seen in nature, metal ions play an important role in this self-organization process, and the overall structure of metalloproteins is primarily the result of two driving forces: the metal coordination preference and the fold of the polypeptide backbone. Previous work in our group has shown that metal ions such as As(III) and Hg(II) can be used to enforce different aggregation states in the Cys derivatives of the designed homotrimeric coiled-coil TRI family [Ac-G(LKALEEK)(4)G-CONH2]. We are now interested in studying the interplay between the metal ion and peptide preferences in controlling the specificity and relative orientation of the alpha-helices in coiled coils. For this objective, two derivatives of the TRI family, TRi L2WL9C and TRi L2WL23C, have been synthesized. Along with those two peptides, two derivatives of Coil-Ser, CSL9C and CSL19C (CS) Ac-EWEALEKKLAALESKLQALEKKLEALEHG-CONH2), a similar de novo designed three-stranded coiled coil that has the potential to form antiparallel coiled coils, have also been used. Circular dichroism, UV-vis, and Hg-199 and Cd-113 NMR spectroscopy results reveal that the addition of Hg(II) and Cd(II) to the different mixtures of these peptides forms preferentially homotrimeric coiled coils, over a statistical population of heterotrimeric parallel and antiparallel coiled coils.