Two distinct segments of the hepatitis B virus surface antigen contribute synergistically to its association with the viral core particles
Two distinct segments of the hepatitis B virus surface antigen contribute synergistically to its association with the viral core particles
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DOI：
10.1006/jmbi.1998.2525
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发表时间：
1999-02-26
影响因子：
5.6
通讯作者：
Murray, K
中科院分区：
文献类型：
--
作者：
Tan, WS;Dyson, MR;Murray, K
B肝炎病毒（HBV）的长表面抗原多肽（L-HBsAg）被认为介导病毒包膜与核衣壳蛋白（HBcAg）之间的接触。将L-HBsAg的N和C末端逐渐缩短，以确定含有与HBcAg结合所需残基的最小连续氨基酸序列。在兔网织红细胞裂解物中表达所得到的突变体，并用免疫沉淀试验和溶液中的平衡结合试验检查它们与HBcAg的相互作用，以得到相对解离常数。L-HBsAg与HBcAg颗粒的结合显示出两个差异很大的解离常数，表明分子之间存在两个不同的结合位点。这两个不同的位点，一个位于残基24和191之间，另一个位于残基191和322之间的L-HBsAg，协同地有助于与HBcAg的高亲和力结合，但这些片段中的任何一个的破坏导致弱得多的相互作用，仅显示一个解离常数。结合到核衣壳刺突尖端的肽对相互作用的抑制区分了HBcAg中L-HBsAg中两个结合结构域的接触，并暗示氨基末端结合结构域接触HBcAg刺突的尖端。对L-HBsAg特异性单氨基酸突变体的分析表明，Arg 92在相互作用中起重要作用。(C)北京：科学出版社.
The long surface antigen polypeptide (L-HBsAg) of hepatitis B virus (HBV) is believed to mediate contact between the virus envelope and nucleocapsid protein (HBcAg). The N and C termini of L-HBsAg were shortened progressively in order to define the minimum contiguous sequence of amino acids that contains the residues necessary for association with HBcAg. The resulting mutants were expressed in rabbit reticulocyte lysates and their interaction with HBcAg was examined with an immunoprecipitation assay and an equilibrium binding assay in solution to give relative dissociation constants. Binding of HBcAg particles by L-HBsAg displayed two widely differing dissociation constants, indicating two distinct binding sites between the molecules. The two distinct sites, one located between residues 24 and 191 and the other between residues 191 and 322 of L-HBsAg, contribute synergistically to high-affinity binding to HBcAg, but disruption of either of these segments resulted in a much weaker interaction showing only one dissociation constant. Inhibition of the interaction by peptides that bind to the tips of the nucleocapsid spikes differentiated contacts in HBcAg for the two binding domains in L-HBsAg and implied that the amino-terminal binding domain contacts the tips of the HBcAg spikes. Analysis of specific single amino acid mutants of L-HBsAg showed that Arg92 played an important role in the interaction. (C) 1999 Academic Press.