Zhou Tianjun, Sun Liguang, Humphreys John, Goldsmith Elizabeth J
Department of Biochemistry, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
Structure. 2006 Jun;14(6):1011-9. doi: 10.1016/j.str.2006.04.006.
MAP kinases bind activating kinases, phosphatases, and substrates through docking interactions. Here, we report a 1.9 A crystallographic analysis of inactive ERK2 bound to a "D motif" docking peptide (pepHePTP) derived from hematopoietic tyrosine phosphatase, a negative regulator of ERK2. In this complex, the complete D motif interaction defined by mutagenic analysis is observed, including extensive electrostatic interactions with the "CD" site of the kinase. Large conformational changes occur in the activation loop where the dual phosphorylation sites, which are buried in the inactive form of ERK2, become exposed to solvent in the complex. Similar conformational changes occur in a complex between ERK2 and a MEK2 (MAP/ERK kinase-2)-derived D motif peptide (pepMEK2). D motif peptides are known to bind homologous loci in the MAP kinases p38alpha and JNK1, also inducing conformational changes in these enzymes. However, the binding interactions and conformational changes are unique to each, thus contributing to specificity among MAP kinases.
丝裂原活化蛋白激酶（MAP激酶）通过对接相互作用与激活激酶、磷酸酶及底物相结合。在此，我们报告了对与源自造血酪氨酸磷酸酶（ERK2的一种负调控因子）的“D基序”对接肽（pepHePTP）结合的无活性ERK2进行的1.9埃晶体学分析。在该复合物中，观察到了通过诱变分析确定的完整D基序相互作用，包括与激酶“CD”位点的广泛静电相互作用。在激活环中发生了大的构象变化，其中在ERK2的无活性形式中被掩埋的双磷酸化位点在复合物中暴露于溶剂中。在ERK2与源自MEK2（丝裂原活化蛋白激酶/细胞外信号调节激酶激酶2）的D基序肽（pepMEK2）形成的复合物中也发生了类似的构象变化。已知D基序肽与MAP激酶p38α和JNK1中的同源位点结合，也会在这些酶中诱导构象变化。然而，结合相互作用和构象变化在每种情况下都是独特的，从而促成了MAP激酶之间的特异性。
