Sekharudu C Y, Sundaralingam M
Department of Chemistry, Ohio State University, Columbus 43210.
Protein Sci. 1993 Apr;2(4):620-5. doi: 10.1002/pro.5560020412.
In the crystal structure of troponin C, the holo C-domain is bound in a head-to-tail fashion to the A-helix of the apo N-domain of a symmetry-related molecule. Using this interaction, we have proposed a model for the calmodulin-peptide complex. We find that the interaction of the C-domain with the A-helix is similar to that observed in the NMR structure of the calmodulin-myosin light chain kinase (MLCK) peptide complex. This similarity in binding has enabled us to make a precise sequence alignment of the target peptides in the calmodulin-binding cleft and to rationalize the amino acid sequence-dependent binding strengths of various peptides. Our model differs from that proposed by Strynadka and James (Proteins Struct. Funct. Genet. 7, 234-248, 1990) in that the peptides are rotated by 100 degrees in the calmodulin binding cleft.
在肌钙蛋白C的晶体结构中，全C结构域以头对尾的方式与对称相关分子的脱辅基N结构域的A螺旋结合。利用这种相互作用，我们提出了一种钙调蛋白-肽复合物的模型。我们发现C结构域与A螺旋的相互作用类似于在钙调蛋白-肌球蛋白轻链激酶（MLCK）肽复合物的NMR结构中观察到的相互作用。这种结合的相似性使我们能够在钙调蛋白结合裂隙中对靶肽进行精确的序列比对，并合理化各种肽的氨基酸序列依赖性结合强度。我们的模型与Strynadka和James（《蛋白质结构、功能与遗传学》7，234 - 248，1990）提出的模型不同，在于肽在钙调蛋白结合裂隙中旋转了100度。
