MHCL RESTRICTED TCR RECOGNITION--STRUCTURAL BASIS

描述(改编自研究人员摘要)：可溶性T细胞 受体(TCR)已被设计用于Lec3.2.8.1 CHO细胞的分泌 它合成了均匀的糖罐；使用亮氨酸拉链来促进 A-b链缔合。两个小鼠TCR，n15和n26，专用于水泡 KB类中的口炎病毒八肽(VSV8) 分子，已经用这种方法表达了。N15和N26的晶体 与抗CB单抗Fab(FabH57)和抗CB单抗Fab络合 得到了N15-VSV8/Kb和N26-VSV8/Kb络合物。的结构 N15-FabN15络合物已被分子分解到2.8A分辨率 结合硒蛋氨酸/MAD分期进行替换。该结构 将N15 TCR与其他免疫球蛋白超家族成员的基因进行比较， 包括抗体、CD4、VCAM-1和CD2。通过比较两个 在不对称单元的N15-FabH57晶体中形成络合物，这是可能的 确定V-V、V-C和/或C-C之间是否存在本征迁移率 TCR的域。N15-VSV8/Kb复合体的结构将被解决 通过使用衍射到3A分辨率的晶体进行分子置换。 将确定单个CDR在多肽/MHC识别中的作用 以及通过比较结构来分析任何与抗原结合相匹配的诱导 TCR-VSV8/Kb与TCR-Fab复合体中CDRs的比例。结构分析 还将进行与VSV8/Kb复合的n26 TCR，以便 确定两个不同的TCR如何结合相同的多肽/MHC配体。这 应该确定对接模式是固定的还是可变的，以及 特定的CDR和MHC之间的相互作用受到限制 多肽残留物。

DESCRIPTION (Adapted from Investigator's abstract): Soluble T cell receptors (TCRs) have been engineered for secretion by Lec3.2.8.1 CHO cells which synthesize homogeneous gylcans; a leucine zipper is used to facilitate a-b chain association. Two mouse TCRs, N15 and N26, specific for vesicular stomatitis virus octapeptide (VSV8) in the context of the Kb class I molecule, have been expressed by this method. Crystals of N15 and N26 complexed with the Fab of an anti-Cb monoclonal antibody (FabH57) and of the N15-VSV8/Kb and N26-VSV8/Kb complexes have been obtained. The structure of the N15-FabN15 complex has been solved to 2.8 A resolution by molecular replacement in conjunction with selenomethionine/MAD phasing. The structure of the N15 TCR will be compared with that of other Ig superfamily members, including antibodies, CD4, VCAM-1 and CD2. By comparing each of two complexes in the asymmetric unit of N15-FabH57 crystals, it may be possible to ascertain whether there is intrinsic mobility between V-V, V-C and/or C-C domains of the TCR. The structure of the N15-VSV8/Kb complex will be solved by molecular replacement using crystals which diffract to 3 A resolution. The role of individual CDRs in peptide/MHC recognition will be determined and any induced fit upon antigen binding analyzed by comparing the structure of the CDRs in the TCR-VSV8/Kb versus TCR-Fab complex. Structure analysis of the N26 TCR complexed with VSV8/Kb will also be carried out in order to determine how two different TCRs bind the same peptide/MHC ligand. This should establish whether the docking mode is fixed or variable and whether there are restricted interactions between specific CDRs and MHC versus peptide residues.