SOLUTION STRUCTURE OF A CALMODULIN-TARGET PEPTIDE COMPLEX BY MULTIDIMENSIONAL NMR
SOLUTION STRUCTURE OF A CALMODULIN-TARGET PEPTIDE COMPLEX BY MULTIDIMENSIONAL NMR
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DOI：
10.1126/science.1585175
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发表时间：
1992-05-01
期刊：
影响因子：
56.9
通讯作者：
BAX, A
中科院分区：
文献类型：
--
作者：
IKURA, M;CLORE, GM;BAX, A
利用多维异核滤波和分离核磁共振波谱技术，确定了钙结合钙调蛋白（Ca²⁺ - CaM）与一个包含骨骼肌肌球蛋白轻链激酶钙调蛋白结合结构域（残基577至602）的26个残基的合成肽之间复合物的三维溶液结构。CaM的两个结构域（残基6至73和83至146）在形成复合物时基本保持不变。然而，在Ca²⁺ - CaM晶体结构中连接两个结构域的长中央螺旋（残基65至93）被打断为两个螺旋，由一个长的柔性环（残基74至82）连接，从而使两个结构域能够夹住结合肽的残基3至21，这些残基呈螺旋构象。复合物的整体结构是球状的，近似一个尺寸为47×32×30埃的椭球体。螺旋肽位于一个疏水通道中，该通道以与长轴约成45度的角度穿过椭球体中心。复合物主要通过疏水相互作用稳定，从CaM方面来看，涉及数量异常多的甲硫氨酸。肽的关键残基是色氨酸4和苯丙氨酸17，它们分别将肽的氨基末端和羧基末端部分锚定到CaM的羧基末端和氨基末端结构域。序列比较表明，许多与CaM高亲和力结合的肽都具有这一共同特征，即包含芳香族残基或长链疏水残基，中间间隔12个残基，这表明它们以类似的方式与CaM相互作用。
The three-dimensional solution structure of the complex between calcium-bound calmodulin (Ca2+-CaM) and a 26-residue synthetic peptide comprising the CaM binding domain (residues 577 to 602) of skeletal muscle myosin light chain kinase, has been determined using multidimensional heteronuclear filtered and separated nuclear magnetic resonance spectroscopy. The two domains of CaM (residues 6 to 73 and 83 to 146) remain essentially unchanged upon complexation. The long central helix (residues 65 to 93), however, which connects the two domains in the crystal structure of Ca2+-CaM, is disrupted into two helices connected by a long flexible loop (residues 74 to 82), thereby enabling the two domains to clamp residues 3 to 21 of the bound peptide, which adopt a helical conformation. The overall structure of the complex is globular, approximating an ellipsoid of dimensions 47 by 32 by 30 angstroms. The helical peptide is located in a hydrophobic channel that passes through the center of the ellipsoid at an angle of approximately 45-degrees with its long axis. The complex is mainly stabilized by hydrophobic interactions which, from the CaM side, involve an unusually large number of methionines. Key residues of the peptide are Trp4 and Phe17, which serve to anchor the amino- and carboxyl-terminal halves of the peptide to the carboxyl- and amino-terminal domains of CaM, respectively. Sequence comparisons indicate that a number of peptides that bind CaM with high affinity share this common feature containing either aromatic residues or long-chain hydrophobic ones separated by a stretch of 12 residues, suggesting that they interact with CaM in a similar manner.