Ikura M, Barbato G, Klee C B, Bax A
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
Cell Calcium. 1992 Jun-Jul;13(6-7):391-400. doi: 10.1016/0143-4160(92)90052-t.
The solution structure of Ca2+ ligated calmodulin and of its complex with a 26-residue peptide fragment of skeletal muscle myosin light chain kinase (skMLCK) have been investigated by multi-dimensional NMR. In the absence of peptide, the two globular domains of calmodulin adopt the same structure as observed in the crystalline form. The so-called 'central helix' which is observed in the crystalline state is disrupted in solution. 15N relaxation studies show that residues Asp78 through Ser81, located near the middle of this 'central helix', form a very flexible link between the two globular domains. In the presence of skMLCK target peptide, the peptide-protein complex adopts a globular ellipsoidal shape. The helical peptide is located in a hydrophobic channel that goes through the center of the complex and makes an angle of approximately 45 degrees with the long axis of the ellipsoid.
已通过多维核磁共振研究了钙离子结合钙调蛋白及其与骨骼肌肌球蛋白轻链激酶（skMLCK）的26个残基肽片段形成的复合物的溶液结构。在没有肽的情况下，钙调蛋白的两个球状结构域采用与晶体形式中观察到的相同结构。在晶体状态下观察到的所谓“中央螺旋”在溶液中被破坏。15N弛豫研究表明，位于该“中央螺旋”中部附近的天冬氨酸78至丝氨酸81残基在两个球状结构域之间形成了非常灵活的连接。在存在skMLCK靶肽的情况下，肽-蛋白质复合物呈球状椭圆形。螺旋肽位于穿过复合物中心的疏水通道中，并与椭圆体的长轴成约45度角。
