Culver G M, McCraith S M, Consaul S A, Stanford D R, Phizicky E M
Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA.
J Biol Chem. 1997 May 16;272(20):13203-10. doi: 10.1074/jbc.272.20.13203.
The last step of tRNA splicing in the yeast Saccharomyces cerevisiae is catalyzed by an NAD-dependent 2'-phosphotransferase, which transfers the splice junction 2'-phosphate from ligated tRNA to NAD to produce ADP-ribose 1"-2" cyclic phosphate. We have purified the phosphotransferase about 28,000-fold from yeast extracts and cloned its structural gene by reverse genetics. Expression of this gene (TPT1) in yeast or in Escherichia coli results in overproduction of 2'-phosphotransferase activity in extracts. Tpt1 protein is essential for vegetative growth in yeast, as demonstrated by gene disruption experiments. No obvious binding motifs are found within the protein. Several candidate homologs in other organisms are identified by searches of the data base, the strongest of which is in Schizosaccharomyces pombe.
酿酒酵母中tRNA剪接的最后一步由一种依赖NAD的2'-磷酸转移酶催化，该酶将连接的tRNA上的剪接连接点2'-磷酸转移至NAD，生成ADP-核糖1''-2''环磷酸酯。我们已从酵母提取物中纯化该磷酸转移酶约28,000倍，并通过反向遗传学克隆了其结构基因。该基因（TPT1）在酵母或大肠杆菌中的表达导致提取物中2'-磷酸转移酶活性过量产生。基因破坏实验表明，Tpt1蛋白对酵母的营养生长至关重要。在该蛋白中未发现明显的结合基序。通过数据库搜索鉴定出其他生物体中的几个候选同源物，其中最强的是在粟酒裂殖酵母中。
