Gibson W, Marcy A I, Comolli J C, Lee J
Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
J Virol. 1990 Mar;64(3):1241-9. doi: 10.1128/JVI.64.3.1241-1249.1990.
The 37-kilodalton (kDa) assembly protein of cytomegalovirus (strain Colburn) B capsids is shown to have a 40-kDa precursor. Pulse-chase radiolabeling experiments revealed that conversion of the precursor to the product was slow, requiring over 6 h for completion, and correlated with movement from the cytoplasmic to the nuclear fraction of Nonidet P-40-disrupted cells. Of these two proteins, only the 40-kDa precursor was synthesized in vitro from infected-cell RNA, consistent with its being the primary translation product. Amino acid sequence data obtained from CNBr-treated, high-performance liquid chromatography-purified assembly protein indicated that precursor translation begins at the first of two closely spaced potential initiation sites and that precursor maturation involves the loss of at least 32 amino acids from its carboxy-terminal end. It is also shown by immunological cross-reactivity and peptide similarity that three low-abundance B-capsid proteins (i.e., the 45-kilodalton [45K], 39K, and 38K proteins) are closely related to the assembly protein; the nature of this relatedness is discussed.
巨细胞病毒（科尔本株）B衣壳的37千道尔顿（kDa）组装蛋白显示有一个40 kDa的前体。脉冲追踪放射性标记实验表明，前体向产物的转化很缓慢，需要超过6小时才能完成，并且与从Nonidet P - 40裂解细胞的细胞质部分向核部分的移动相关。在这两种蛋白质中，只有40 kDa的前体是由感染细胞的RNA在体外合成的，这与其作为主要翻译产物一致。从经溴化氰处理、高效液相色谱纯化的组装蛋白获得的氨基酸序列数据表明，前体翻译始于两个紧密相邻的潜在起始位点中的第一个，并且前体成熟涉及从其羧基末端至少丢失32个氨基酸。免疫交叉反应和肽相似性还表明，三种低丰度的B衣壳蛋白（即45千道尔顿[45K]、39K和38K蛋白）与组装蛋白密切相关；讨论了这种相关性的性质。
