Sutton R B, Davletov B A, Berghuis A M, Südhof T C, Sprang S R
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.
Cell. 1995 Mar 24;80(6):929-38. doi: 10.1016/0092-8674(95)90296-1.
C2 domains are regulatory sequence motifs that occur widely in nature. Synaptotagmin I, a synaptic vesicle protein involved in the Ca2+ regulation of exocytosis, contains two C2 domains, the first of which acts as a Ca2+ sensor. We now describe the three-dimensional structure of this C2 domain at 1.9 A resolution in both the Ca(2+)-bound and Ca(2+)-free forms. The C2 polypeptide forms an eight-stranded beta sandwich constructed around a conserved four-stranded motif designated as a C2 key. Ca2+ binds in a cup-shaped depression between two polypeptide loops located at the N- and C-termini of the C2-key motif.
C2结构域是自然界中广泛存在的调控序列基序。突触结合蛋白I是一种参与胞吐作用的Ca2+调节的突触囊泡蛋白，它含有两个C2结构域，其中第一个作为Ca2+传感器。我们现在描述了这个C2结构域在1.9埃分辨率下Ca(2+)结合和无Ca(2+)形式的三维结构。C2多肽形成一个围绕着一个保守的四链基序（称为C2键）构建的八链β折叠三明治结构。Ca2+结合在位于C2键基序N端和C端的两个多肽环之间的杯状凹陷中。
