QA-2 MOLECULES ARE PEPTIDE RECEPTORS OF HIGHER STRINGENCY THAN ORDINARY CLASS-I MOLECULES
QA-2 MOLECULES ARE PEPTIDE RECEPTORS OF HIGHER STRINGENCY THAN ORDINARY CLASS-I MOLECULES
复制标题
DOI：
10.1038/361642a0
复制
发表时间：
1993-02-18
期刊：
影响因子：
64.8
通讯作者：
RAMMENSEE, HG
中科院分区：
文献类型：
--
作者：
ROTZSCHKE, O;FALK, K;RAMMENSEE, HG
主要组织相容性复合体（MHC）的I类分子将肽运输到细胞表面，以供T细胞监测。配体特异性要求严格，并且在不同等位基因之间存在差异。在此我们报道对“非经典的”糖磷脂酰肌醇锚定的小鼠I类分子Qa - 2的天然配体的分析。这些分子的功能尚不清楚；它们可作为“非限制性”细胞毒性T细胞的识别结构，但尚未发现其向T细胞呈递肽，尽管其DNA序列表明其具有与“经典的”I类分子相似的肽结合槽，并且在少数情况下其他非经典的I类分子能够呈递抗原。对天然Qa - 2配体的混合测序表明，Qa - 2分子确实是肽受体，其配体特异性与经典的I类分子相似，即主要的肽长度为9个氨基酸，具有锚定位点以及肽的疏水性末端。但是其配体特异性比其他I类分子更为严格：在9个位置中，2个是锚定位点，并且4个位置的占有率相当有限。
CLASS I molecules of the major histocompatibility complex (MHC) transport peptides to the cell surface for surveillance by T cells1. Ligand specificity is stringent and differs from allele to allele2-4. Here we report analysis of natural ligands of 'unconventional' glycophosphatidyl-anchored mouse class I molecules, Qa-2. The function of these molecules is unclear5,6; they can serve as recognition structures for 'unrestricted' cytotoxic T cells but have not been found to present peptides to T cells, although the DNA sequence suggests a similar peptide binding groove to that of 'conventional' class I molecules7, and other unconventional class I molecules can present antigens in a few cases8-10. Pool sequencing of natural Qa-2 ligands shows that Qa-2 molecules are indeed peptide receptors, having ligand specificity similar to that of conventional class I molecules, that is, a predominant length of nine amino acids, anchor positions, and hydrophobic termination of peptides. But ligand specificity is much more stringent than with other class I molecules: of the nine positions, two are anchors and four have rather limited occupancy.