Brito L, Vieira G, Santos M A, Paveia H
Departamento de Botânica e Engenharia Biológica-Microbiologia, Instituto Superior de Agronomia, Lisboa, Portugal.
Plasmid. 1996 Jul;36(1):49-54. doi: 10.1006/plas.1996.0031.
Analysis of the nucleotide sequence of Leuconostoc oenos plasmid pOg32 (2544 bp) revealed three open reading frames (ORFs) in one of the DNA strands preceded by putative promoters and ribosome binding sites. ORF1 corresponded to a polypeptide similar to the replication proteins (Rep) of pT181 plasmid family. A nucleotide sequence like the double strand origin (DSO) of the same plasmid family was found inside the presumptive rep gene. ORF2 is capable of encoding a protein resembling the recombination enzyme (Pre) of two lactobacilli plasmids. Immediately upstream of the presumed pre gene, a sequence similar to the consensus RSA regions of those plasmids was encountered. Between ORF3 and ORF1, a sequence comparable to the RSB consensus region of the single strand origin ssoA was detected. The putative RSB region was located at the 3'-end of an imperfect palindrome which may be a single stranded origin. The described features, common to other small plasmids of Gram-positive bacteria, suggest that pOg32 replicates by the rolling circle mechanism. The amino acid sequence encoded by ORF3 was not similar to any known protein.
对酒酒球菌质粒pOg32（2544 bp）的核苷酸序列分析显示，在一条DNA链上有三个开放阅读框（ORF），其前面有假定的启动子和核糖体结合位点。ORF1对应于一种与pT181质粒家族的复制蛋白（Rep）相似的多肽。在假定的rep基因内部发现了一个与同一质粒家族的双链起源（DSO）相似的核苷酸序列。ORF2能够编码一种类似于两种乳杆菌质粒的重组酶（Pre）的蛋白质。在假定的pre基因上游紧邻处，遇到了一个与那些质粒的共有RSA区域相似的序列。在ORF3和ORF1之间，检测到一个与单链起源ssoA的RSB共有区域相当的序列。假定的RSB区域位于一个不完全回文的3'端，该不完全回文可能是一个单链起源。所述特征是革兰氏阳性菌其他小质粒所共有的，这表明pOg32通过滚环机制进行复制。ORF3编码的氨基酸序列与任何已知蛋白质都不相似。
