Klein R, Greineder B, Baranyi U, Witte A
Institute of Microbiology and Genetics, University of Vienna, Dr. Bohr-Gasse 9, Vienna, A-1030, Austria.
Virology. 2000 Oct 25;276(2):376-87. doi: 10.1006/viro.2000.0565.
phiCh1 is a lysogenic virus for the haloalkalophilic archaeon Natrialba magadii. The virus morphology resembles other members of Myoviridae infecting Halobacterium species. The gene of the major capsid protein E of virus phiCh1 was cloned and the DNA sequence was determined. Gene E was mapped to a 3.2-kbp ClaI fragment, localized to the 5'-end of the phiCh1 genome. The complete nucleotide sequence of this region was determined and the identity of gene E was confirmed by comparing the experimentally determined N-terminal amino acid sequence of the purified protein to the translated DNA sequence of its open reading frame. We present evidence that the gene E product is proteolytically cleaved between Lys(16) and Asn(17) to yield the 305 residue polypeptides found in the mature viral capsid. Processing of the protein itself during virus development was determined by 2D gel electrophoresis using protein E-specific antibodies. Sequence similarity studies revealed an 80% identity to capsid protein Hp32 of phiH, infecting Halobacterium salinarum. RT-PCR analysis as well as Western blot studies revealed gene E as a late gene. Transcripts and proteins could be detected shortly before onset of lysis of the lysogenic strain N. magadii L11.
phiCh1是嗜盐碱古菌纳氏嗜盐碱杆菌（Natrialba magadii）的一种溶源性病毒。该病毒形态类似于感染嗜盐杆菌属物种的肌尾噬菌体科的其他成员。克隆了病毒phiCh1的主要衣壳蛋白E的基因并测定了DNA序列。基因E定位于一个3.2千碱基对的ClaI片段，位于phiCh1基因组的5'端。测定了该区域的完整核苷酸序列，并通过将纯化蛋白的实验测定的N端氨基酸序列与其开放阅读框的翻译DNA序列进行比较，确认了基因E的身份。我们提供的证据表明，基因E产物在赖氨酸（16）和天冬酰胺（17）之间被蛋白水解切割，产生成熟病毒衣壳中发现的305个残基的多肽。在病毒发育过程中蛋白质本身的加工过程通过使用蛋白E特异性抗体的二维凝胶电泳来确定。序列相似性研究表明，与感染盐沼嗜盐杆菌（Halobacterium salinarum）的phiH的衣壳蛋白Hp32有80%的同一性。逆转录聚合酶链反应（RT-PCR）分析以及蛋白质印迹研究表明基因E是一个晚期基因。在溶源性菌株纳氏嗜盐碱杆菌L11裂解开始前不久可以检测到转录本和蛋白质。
