Eppstein D A, Thoma J A
Biochem J. 1977 Nov 1;167(2):321-32. doi: 10.1042/bj1670321.
The intact matrix protein from a nuclear-polyhedrosis virus of the cabbage looper (Trichoplusia ni), isolated after inhibition of an endogenous serine-type proteinase, was further purified by molecular-sieve chromatography. The matrix protein was associated with carbohydrate moieties, and the carbohydrate content was determined for the two major peptides isolated after proteolysis by the endogenous proteinase. The association-dissociation interactions of the intact and proteinase-hydrolysed monomer units were characterized at high and low pH. At pH1.9, proteinase-degraded matrix protein dissociated into two different peptide fractions, FI and FII. Fraction FII, a single peptide of 9400 daltons, comprised one-third of the monomer unit of 28 000 daltons. At pH9.5, the degraded peptides were tightly associated in units equivalent to the intact monomer. These monomer equivalents associated to form a series of interconverting aggregates. The predominant aggregate sedimented at 11S and had a mol.wt greater than or equal to 200 000. Two non-cross-reacting antigens were present in the aggregate mixture. The presence of these two antigens does not reflect the presence of two different matrix proteins; rather, the expression of the antigens correlates with the degree of aggregation of the matrix protein.
通过抑制内源性丝氨酸型蛋白酶后分离得到的甘蓝夜蛾（Trichoplusia ni）核型多角体病毒的完整基质蛋白，经分子筛色谱进一步纯化。该基质蛋白与碳水化合物部分相关联，并且对内源性蛋白酶水解后分离得到的两种主要肽段的碳水化合物含量进行了测定。在高pH和低pH条件下，对完整的和蛋白酶水解后的单体单元的缔合-解离相互作用进行了表征。在pH1.9时，蛋白酶降解的基质蛋白解离成两种不同的肽段，即FⅠ和FⅡ。FⅡ是一种分子量为9400道尔顿的单一肽段，占28000道尔顿单体单元的三分之一。在pH9.5时，降解的肽段紧密缔合形成与完整单体相当的单元。这些单体等价物缔合形成一系列相互转化的聚集体。主要的聚集体在11S处沉降，分子量大于或等于200000。聚集体混合物中存在两种不发生交叉反应的抗原。这两种抗原的存在并不反映存在两种不同的基质蛋白；相反，抗原的表达与基质蛋白的聚集程度相关。
