Shao X, Davletov B A, Sutton R B, Südhof T C, Rizo J
Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235, USA.
Science. 1996 Jul 12;273(5272):248-51. doi: 10.1126/science.273.5272.248.
C2 domains are found in many proteins involved in membrane traffic or signal transduction. Although C2 domains are thought to bind calcium ions, the structural basis for calcium binding is unclear. Analysis of calcium binding to C2 domains of synaptotagmin I and protein kinase C-beta by nuclear magnetic resonance spectroscopy revealed a bipartite calcium-binding motif that involves the coordination of two calcium ions by five aspartate residues located on two separate loops. Sequence comparisons indicated that this may be a widely used calcium-binding motif, designated here as the C2 motif.
C2结构域存在于许多参与膜运输或信号转导的蛋白质中。尽管人们认为C2结构域能结合钙离子，但其钙结合的结构基础尚不清楚。通过核磁共振光谱对与突触结合蛋白I和蛋白激酶C-β的C2结构域的钙结合分析，揭示了一种双部分钙结合基序，该基序涉及位于两个不同环上的五个天冬氨酸残基对两个钙离子的配位。序列比较表明，这可能是一种广泛使用的钙结合基序，在此处命名为C2基序。
