Daniels D L, Cohen A R, Anderson J M, Brünger A T
The Howard Hughes Medical Institute and Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
Nat Struct Biol. 1998 Apr;5(4):317-25. doi: 10.1038/nsb0498-317.
PDZ domain containing proteins assist formation of cell-cell junctions and localization of membrane protein receptors and ion channels. PDZ domains interact with the C-terminal residues of a particular target membrane protein. Based on their binding specificities and sequence homologies, PDZ domains fall into two classes. The first crystal structure of a class II PDZ domain, that of hCASK, has been solved by multi-wavelength anomalous dispersion phasing. Complex formation with the C-terminus of a neighboring non-crystallographically related PDZ domain reveals interactions between hCASK and its ligand. Class II PDZ domains differ from class I domains by formation of a second hydrophobic binding pocket. The C-terminal carboxylate binding loop of the PDZ domain is structurally conserved in both classes suggesting a generalized carboxylate binding motif (h-Gly-h) where h is a hydrophobic residue.
含PDZ结构域的蛋白质有助于细胞间连接的形成以及膜蛋白受体和离子通道的定位。PDZ结构域与特定靶膜蛋白的C末端残基相互作用。根据其结合特异性和序列同源性，PDZ结构域可分为两类。II类PDZ结构域hCASK的首个晶体结构已通过多波长反常色散相位法解析。与相邻非晶体学相关PDZ结构域的C末端形成复合物揭示了hCASK与其配体之间的相互作用。II类PDZ结构域与I类结构域的不同之处在于形成了第二个疏水结合口袋。PDZ结构域的C末端羧酸盐结合环在两类结构域中在结构上都是保守的，这表明存在一个通用的羧酸盐结合基序（h-Gly-h），其中h是一个疏水残基。
