Subunit interactions of class I histocompatibility antigens.
Subunit interactions of class I histocompatibility antigens.
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I 类组织相容性抗原的亚基相互作用。
DOI：
10.1021/bi00341a039
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发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
Strominger,JL
中科院分区：
文献类型：
--
作者：
Parker,KC;Strominger,JL
生物化学和分子生物学系，哈佛大学，剑桥，马萨诸塞州02138接收于1985年2月21日摘要：研究了碘化d2-微球蛋白（d2 m）从木瓜蛋白酶溶解的I类组织相容性抗原HLA-B7上解离的动力学。在未标记的/32 m的存在下，大多数HLA根据单一速率常数解离，而在未标记的/32 m的不存在下，系统接近依赖于初始HLA浓度的平衡。当碘化β 2与未标记的HLA-B7孵育时，β 2掺入复合物的速率对浓度的依赖性比简单缔合/解离系统的预期要小得多;相反，该系统的行为似乎HLA重链中间体的“活性”（在热力学意义上）不能超过临界浓度。每种I类特异性的解离速率是温度、离子强度、pH和重链状态（木瓜蛋白酶溶解vs.去污剂溶解）的函数。高温、高离子强度和pH值的极限促进解离。完整分子的解离速度比木瓜蛋白酶溶解的分子慢约10倍。相反，所有测试的pa-疼痛溶解的I类抗原的解离速率福尔斯在约2倍的范围内。碳水化合物的存在对解离速率没有影响。HLA-I类抗原解离的可能性可能发生在体内酸性的内部囊泡进行了讨论。
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138 Received February 21, 1985 abstract: The kinetics of dissociation of iodinated d2-microglobulin (d2m) from the papain-solubilized class I histocompatibility antigen HLA-B7 have been investigated. In the presence of unlabeled/32m, most of the HLA dissociates according to a single rate constant, whereas in the absence of unlabeled/32m, the system approaches an equilibrium dependent upon the initial HLA concentration. When iodinated ß2 is incubated with unlabeled HLA-B7, the rate of incorporation of ß2 into the complex is much less dependent on the concentration than is expected for a simple association/dissociation system; instead, the systembehaves as if the “activity”(in a thermodynamic sense) of the HLA heavy-chain intermediate cannot surpass a critical concentration. The dissociation rate for each class I specificity is a function of temperature, ionic strength, pH, and the status of the heavy chain (papain solubilized vs. detergent solubilized). High temperature, high ionic strength, andextremes of pH promote dissociation. The intact molecule dissociates about 10 times more slowly than the papain-solubilized molecule. In contrast, the rate of dissociation of all pa-pain-solubilized class I antigens tested falls within the range of about a factor of 2. The presence of the carbohydrate has no effect on the rate of dissociation. The possibilitythat HLA class I antigen dissociation may occur in vivo within acidic internal vesicles is discussed.