Eggers M, Boes-Fabian B, Ruppert T, Kloetzel P M, Koszinowski U H
Abteilung Virologie, Ruprecht-Karls Universität Heidelberg, Germany.
J Exp Med. 1995 Dec 1;182(6):1865-70. doi: 10.1084/jem.182.6.1865.
Proteasomes degrade endogenous proteins in the cytosol. The potential contribution of the proteasome to the effect of flanking sequences on the presentation of an antigenic epitope presented by the major histocompatibility complex class I allele Ld was studied. Peptides generated in cells from minigenes coding for peptides of 17- and 19-amino acid length were compared with the in vitro 20S proteasome degradation products of the respective synthetic peptides. The quality of generated peptides was independent of ubiquitination. In vivo and in vitro processing products were indistinguishable with respect to peptide size and abundance. Altering the neighboring sequence substantially improved the yield of the final antigenic nonapeptide by 20S proteasome cleavage. These results suggest that, in addition to the presence of major histocompatibility complex class I allelic motifs, the cleavage preference of the proteasome can define the antigenic potential of a protein.
蛋白酶体在细胞质中降解内源性蛋白质。研究了蛋白酶体对侧翼序列对主要组织相容性复合体I类等位基因Ld呈递抗原表位的影响的潜在作用。将编码17和19个氨基酸长度肽段的小基因在细胞中产生的肽段与相应合成肽段的体外20S蛋白酶体降解产物进行了比较。所产生肽段的质量与泛素化无关。体内和体外加工产物在肽段大小和丰度方面没有区别。通过20S蛋白酶体切割改变相邻序列可显著提高最终抗原性九肽的产量。这些结果表明，除了主要组织相容性复合体I类等位基因基序的存在外，蛋白酶体的切割偏好可以定义蛋白质的抗原潜力。
