一种新的嘌呤生物合成酶的克隆与特性分析：来自大肠杆菌的一种非叶酸甘氨酰胺核糖核苷酸转甲酰基酶

Cloning and characterization of a new purine biosynthetic enzyme: a non-folate glycinamide ribonucleotide transformylase from E. coli.

作者信息

Marolewski A, Smith J M, Benkovic S J

机构信息

Department of Chemistry, Pennsylvania State University, University Park 16802.

出版信息

Biochemistry. 1994 Mar 8;33(9):2531-7. doi: 10.1021/bi00175a023.

DOI:10.1021/bi00175a023

PMID:8117714

Abstract

A novel GAR transformylase has been isolated and characterized from E. coli. The protein, a product of the purT gene, is a monomer of molecular weight 42 kDa and catalyzes the production of beta-formyl GAR from formate, ATP, and beta-GAR. As such it is an alternative to the formyl-folate utilizing purN GAR transformylase. No significant homology exists between the two transformylases. However, the purT protein shows significant homology to the purK protein, also involved in purine biosynthesis. Two different purT reactions have been characterized: one producing fGAR from ATP, beta-GAR, and formate and the other producing acetyl phosphate and ADP from acetate and ATP. The purT GAR transformylase is the first unknown de novo purine biosynthetic enzyme to be discovered in the last 30 years and represents another step forward in understanding cellular control of purine levels.

摘要

一种新型的甘氨酰胺核糖核苷酸（GAR）转甲酰酶已从大肠杆菌中分离并鉴定出来。该蛋白质是purT基因的产物，是一种分子量为42 kDa的单体，可催化由甲酸、ATP和β-甘氨酰胺核糖核苷酸（β-GAR）生成β-甲酰甘氨酰胺核糖核苷酸（β-formyl GAR）。因此，它是利用甲酰四氢叶酸的purN GAR转甲酰酶的替代物。这两种转甲酰酶之间不存在显著的同源性。然而，purT蛋白与同样参与嘌呤生物合成的purK蛋白显示出显著的同源性。已鉴定出两种不同的purT反应：一种是由ATP、β-GAR和甲酸生成甲酰甘氨酰胺核糖核苷酸（fGAR），另一种是由乙酸盐和ATP生成乙酰磷酸和ADP。purT GAR转甲酰酶是过去30年来发现的首个未知的从头嘌呤生物合成酶，代表了在理解细胞对嘌呤水平的控制方面又向前迈进了一步。