Fruci D, Greco G, Vigneti E, Tanigaki N, Butler R H, Tosi R
Institute for Cellular Biology, CNR, Rome, Italy.
Hum Immunol. 1994 Sep;41(1):34-8. doi: 10.1016/0198-8859(94)90081-7.
Model peptides have been used to quantitate the effect on HLA-B2705 binding of the spacing between primary anchor residues, the type of amino acid accepted in the P9 anchor position, and the type of amino acid accepted in the "secondary anchor positions" P3 and P7. Peptide binding was measured by the HLA class I alpha-chain-refolding assay. The results obtained show that (a) Among the model peptides differing in the spacing between anchor residues, the nonamer with Arg in P2 and Lys in P9 (R2, K9) has the maximum binding with B2705 molecule. The decamer, with an extra Ala inserted between Arg and Lys (R2, K10), has much lower binding, and still lower binding is observed for the octamer, where an Ala is removed (R2, K8). (b) Besides the "classic" Lys and Arg, several other aminoacids such as Tyr, Leu, Ala, and Gln can be accepted in P9, but with significant differences in binding affinity. (c) Different amino acids in P3 have an influence on peptide binding. Trp and Phe have a favorable influence, whereas Lys and Val appear to hinder the binding. Some variations are seen also for different amino acids in P7.
模型肽已被用于定量主要锚定残基之间的间距、P9锚定位置所接受的氨基酸类型以及“次要锚定位置”P3和P7所接受的氨基酸类型对HLA - B2705结合的影响。通过HLA I类α链重折叠试验测量肽结合。获得的结果表明：(a) 在锚定残基间距不同的模型肽中，P2位为精氨酸（R2）且P9位为赖氨酸（K9）的九聚体与B2705分子的结合力最强。在R2和K9之间插入一个额外丙氨酸的十聚体（R2，K10）结合力低得多，而去除一个丙氨酸的八聚体（R2，K8）结合力更低。(b) 除了“经典”的赖氨酸和精氨酸外，P9位还可接受其他几种氨基酸，如酪氨酸、亮氨酸、丙氨酸和谷氨酰胺，但结合亲和力有显著差异。(c) P3位的不同氨基酸对肽结合有影响。色氨酸和苯丙氨酸有促进作用，而赖氨酸和缬氨酸似乎会阻碍结合。P7位不同氨基酸也有一些差异。
