https://scholars.lib.ntu.edu.tw/handle/123456789/160059
標題: | The Terminal Proteins of Linear Streptomyces Chromosomes and Plasmids: A Novel Class of Replication Priming Proteins | 作者: | LEE, SHENG-CHUNG | 關鍵字: | DNA-REPLICATION;REVERSE-TRANSCRIPTASE;NUCLEOTIDE-SEQUENCE;EARLY REGION;BACTERIOPHAGE-PHI-29;COMPLEX | 公開日期: | 2002 | 卷: | v.43 | 期: | n.2 | 起(迄)頁: | 297-305 | 來源出版物: | MOLECULAR MICROBIOLOGY | 摘要: | The chromosomes of the soil bacteria Streptomyces, unlike those of most other bacteria, are linear DNA molecules. Their telomeres contain long- terminal inverted repeats and covalently bound terminal proteins (TPs). These bacteria also harbour linear plasmids that share the same structural features. In this study, we demonstrated that the TP was covalently bound to the 5' ends as proposed previously. A linear plasmid with chromosomal telomeres was constructed and used to purify the TPs of the Streptomyces coelicolor A3 (2) chromosome. A 20 kDa protein and its 10 kDa degradation product were isolated and their sequences determined by mass spectrometry. The coding sequence (tpgC) was about 100 kb from the right end of the chromosome. Two tpg homologues were identified by sequencing the 50 kb linear plasmid SLP2 of Streptomyces lividans: tpgSLP2 at 6 kb from the left end and a putative tpg pseudogene at 8 kb from the right. The latter was in a terminal repeat shared by the right end of SLP2 and both ends of the S. lividans chromosome. The lack of the typical Streptomyces codon preference in this open reading frame suggests that it is a pseudogene. The close physical linkage between the tpg genes and their cognate telomeres would favour their co-segregation and co-evolution . All the Tpg polypeptides are similar in length (184-185 amino acids) and sequences, which include a putative helix domain that is homologous to part of the DNA-binding 'thumb' domain of HIV reverse transcriptase, and a putative amphiphilic beta-sheet that may be involved in the observed self- aggregation of the TP and/or the proposed membrane binding. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/95065 |
顯示於: | 分子醫學研究所 |
在 IR 系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。