Using diastereopeptides to control metal ion coordination in proteins
Using diastereopeptides to control metal ion coordination in proteins
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DOI：
10.1073/pnas.0806792105
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发表时间：
2008-10-28
影响因子：
11.1
通讯作者：
Pecoraro, Vincent L.
中科院分区：
文献类型：
--
作者：
Peacock, Anna F. A.;Hemmingsen, Lars;Pecoraro, Vincent L.
在这里，我们报告了一个以前未描述的方法，用于控制金属离子的配位几何形状在生物分子中的氨基酸侧链通过取代L-D-氨基酸的重新定向。这些非对映肽使我们能够操纵氨基酸侧链的空间取向，以改变金属结合口袋的空间。我们已经使用这种方法来设计从头金属肽，Cd（TRIL 12 L（D）L16 C）（3）（-），其是与3个L-Cys结合的Cd（II）的一个例子，仅作为三角形CdS 3，如通过Cd-113 NMR和Cd-111 m PAC光谱的组合表征的。我们随后表明，这样的网站，如高pK（a2）为Cd（II）结合15.1的物理性质，是由于配位数的性质，而不是连接基团。此外，该方法允许设计构建体GRANDL 12 L（D）L16 CL 26 AL 30 C，其能够独立地将2当量的Cd（II）结合至2个非常相似的Cys位点，分别为仅3-和4-，CdS 3和CdS 3 O。证明我们是能够控制的Cd（II）的配位数在这2个网站仅仅通过改变一个noncoordinating第二协调领域的氨基酸的性质，与D-亮氨酸和L-丙氨酸导致专门的3-和4-配位结构，分别。镉（II）被发现选择性地结合到4-坐标CdS 3 O网站，表明可以设计一种蛋白质，显示金属结合的选择性仅基于配位数控制，而不是在化学身份的协调配体。
Here, we report a previously undescribed approach for controlling metal ion coordination geometry in biomolecules by reorientating amino acid side chains through substitution of L- to D-amino acids. These diastereopeptides allow us to manipulate the spatial orientation of amino acid side chains to alter the sterics of metal binding pockets. We have used this approach to design the de novo metallopeptide, Cd(TRIL12L(D)L16C)(3)(-), which is an example of Cd(II) bound to 3 L-Cys as exclusively trigonal CdS3, as characterized by a combination of Cd-113 NMR and Cd-111m PAC spectroscopy. We subsequently show that the physical properties of such a site, such as the high pK(a2) for Cd(II) binding of 15.1, is due to the nature of the coordination number and not the ligating group. Furthermore this approach allowed for the design of a construct, GRANDL12L(D)L16CL26AL30C, capable of independently binding 2 equivalents of Cd(II) to 2 very similar Cys sites as exclusively 3- and 4-, CdS3 and CdS3O, respectively. Demonstrating that we are capable of controlling the Cd(II) coordination number in these 2 sites solely by varying the nature of a noncoordinating second coordination sphere amino acid, with D-leucine and L-alanine resulting in exclusively 3- and 4-coordinate structures, respectively. Cd(II) was found to selectively bind to the 4-coordinate CdS3O site, demonstrating that a protein can be designed that displays metalbinding selectivity based solely on coordination number control and not on the chemical identity of coordinating ligands.