Mosyak L, Zaller D M, Wiley D C
Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, USA.
Immunity. 1998 Sep;9(3):377-83. doi: 10.1016/s1074-7613(00)80620-2.
The three-dimensional structure of the soluble ecto-domain of HLA-DM has been determined to 2.5 A resolution by X-ray crystallography. HLA-DM has both peptide exchange activity and acts as a chaperone to peptide-free class II MHC molecules. As predicted, the structure is similar to that of classical class II MHC molecules except that the peptide-binding site is altered to an almost fully closed groove. An unusual cavity is found at the center of the region that binds peptides in class II MHC molecules, and a tryptophanrich lateral surface is identified that is a candidate both for binding to HLA-DR, to effect catalysis, and to HLA-DO, an inhibitor.
通过X射线晶体学已确定HLA-DM可溶性胞外域的三维结构，分辨率达2.5埃。HLA-DM既具有肽交换活性，又作为无肽II类主要组织相容性复合体（MHC）分子的分子伴侣发挥作用。正如所预测的那样，该结构与经典II类MHC分子的结构相似，只是肽结合位点变成了几乎完全封闭的凹槽。在II类MHC分子中结合肽的区域中心发现了一个不寻常的腔，并且鉴定出一个富含色氨酸的侧面，它既是与HLA-DR结合以实现催化作用的候选者，也是与抑制剂HLA-DO结合的候选者。
