Controlling and fine tuning the physical properties of two identical metal coordination sites in de novo designed three stranded coiled coil peptides.
Controlling and fine tuning the physical properties of two identical metal coordination sites in de novo designed three stranded coiled coil peptides.
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DOI：
10.1021/ja104433n
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发表时间：
2011-01-19
影响因子：
15
通讯作者：
Pecoraro, Vincent L.
中科院分区：
文献类型：
--
作者：
Iranzo, Olga;Chakraborty, Saumen;Hemmingsen, Lars;Pecoraro, Vincent L.
在此，我们报告了如何使用从头设计的肽来研究沿着折叠成三链α-螺旋卷曲线圈的线性序列的金属位点的位置是否定义了CdS3或CdS3O（O-是外源水分子）配位环境中Cd(II)离子的物理性质。提出的肽将 Cd(II) 结合到两个相同的配位位点，这两个配位位点位于这些构建体内部的不同拓扑位置。肽 grandL16PenL19IL23PenL26I 结合两个 Cd(II) 作为三角平面 3 配位 CdS3 结构，而 grandL12AL16CL26AL30C 隔离两个 Cd(II) 作为伪四面体 4 配位 CdS3O 结构。我们演示了对于具有更刚性结构的第一个肽，沿着线性序列的相同结合位点的位置如何不会影响两个结合的 Cd(II) 的物理性质。然而，由于这些是刚性聚集体，这些位点并不完全独立，因为与其中一个位点（113Cd NMR 化学位移为 681 ppm）结合的 Cd(II) 受到第二中心（113Cd NMR 化学位移为 686 ppm）的金属化态（apo 或 [Cd(pep)(Hpep)2]+ 或 [Cd(pep)3]−）的干扰。 grandL12AL16CL26AL30C 显示出完全不同的行为。两个结合的 Cd(II) 离子的物理性质确实取决于金属中心的位置，平衡 [Cd(pep)(Hpep)2]+ → [Cd(pep)3]− + 2H+（对应于半胱氨酸硫醇的去质子化和配位）的 pKa2 值范围为 9.9 至 13.9。此外，L26AL30C 位点显示出动态行为，而 L12AL16C 位点未观察到这种行为。这些结果表明，对于这些系统，不能简单地指定“4 配位结构”并假设该位点的某些物理性质，因为诸如相邻 Leu 的堆积、预期空腔的大小（内型与外型）和金属位点的位置等重要因素在确定结合的 Cd(II) 的最终性质中起着至关重要的作用。
Herein we report how de novo designed peptides can be used to investigate whether the position of a metal site along a linear sequence that folds into a three stranded α-helical coiled coil defines the physical properties of Cd(II) ions in either CdS3 or CdS3O (O-being an exogenous water molecule) coordination environments. Peptides are presented that bind Cd(II) into two identical coordination sites that are located at different topological positions at the interior of these constructs. The peptide grandL16PenL19IL23PenL26I binds two Cd(II) as trigonal planar 3-coordinate CdS3 structures whereas grandL12AL16CL26AL30C sequesters two Cd(II) as pseudotetrahedral 4-coordinate CdS3O structures. We demonstrate how for the first peptide, having a more rigid structure, the location of the identical binding sites along the linear sequence does not affect the physical properties of the two bound Cd(II). However, because these are rigid aggregates, the sites are not completely independent as Cd(II) bound to one of the sites (113Cd NMR chemical shift of 681 ppm) is perturbed by the metallation state (apo or [Cd(pep)(Hpep)2]+ or [Cd(pep)3]−) of the second center (113Cd NMR chemical shift of 686 ppm). grandL12AL16CL26AL30C shows a completely different behavior. The physical properties of the two bound Cd(II) ions indeed depend on the position of the metal center, having pKa2 values for the equilibrium [Cd(pep)(Hpep)2]+ → [Cd(pep)3]− + 2H+ (corresponding to deprotonation and coordination of cysteine thiols) that range from 9.9 to 13.9. In addition, the L26AL30C site shows dynamic behavior, which is not observed for the L12AL16C site. These results indicate that for these systems one cannot simply assign a “4-coordinate structure” and assume certain physical properties for that site since important factors such as packing of the adjacent Leu, size of the intended cavity (endo vs exo) and location of the metal site play crucial roles in determining the final properties of the bound Cd(II).
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影响因子：
15
作者：
Ghirlanda, G;Osyczka, A;DeGrado, WF
通讯作者：
DeGrado, WF
影响因子：
15
作者：
Dieckmann, GR;McRorie, DK;Pecoraro, VL
通讯作者：
Pecoraro, VL
影响因子：
2.9
作者：
Calhoun, JR;Nastri, F;DeGrado, WF
通讯作者：
DeGrado, WF
影响因子：
15
作者：
Geremia, S;Di Costanzo, L;DeGrado, WF
通讯作者：
DeGrado, WF
影响因子：
2.9
作者：
Boice, JA;Dieckmann, GR;Fairman, R
通讯作者：
Fairman, R