Zhang P, Vigne J L, Mellon S H
Department of Obstetrics, Gynecology and Reproductive Sciences, The Reproductive Endocrinology Center, University of California, San Francisco 94143-0556, USA.
DNA Cell Biol. 1998 Feb;17(2):169-75. doi: 10.1089/dna.1998.17.169.
Polyribonucleotide phosphorylase (PNPase) is one of the critical components of the E. coli RNA degradosome, which consists of both PNPase and endoribonuclease RNase E. The function of this complex is to control the rate of mRNA degradation. The PNPase possesses two enzymatic activities, namely 3'-5' processive exoribonuclease activity and 5'-3' RNA polymerase activity. In the present study, we used conventional chromatography to purify an E. coli protein that binds to a specific double-stranded DNA sequence. Microsequencing of the purified protein showed that this DNA-binding protein was PNPase. Our data further demonstrate that PNPase binds to DNA in a sequence-specific manner. These data suggest that PNPase may have previously unappreciated DNA-related functions in addition to its known role in mRNA degradation.
多聚核糖核苷酸磷酸化酶（PNPase）是大肠杆菌RNA降解体的关键组成部分之一，该降解体由PNPase和核糖核酸内切酶RNase E组成。这个复合体的功能是控制mRNA的降解速率。PNPase具有两种酶活性，即3'-5' 连续外切核糖核酸酶活性和5'-3' RNA聚合酶活性。在本研究中，我们使用传统色谱法纯化了一种与特定双链DNA序列结合的大肠杆菌蛋白。对纯化蛋白的微量测序表明，这种DNA结合蛋白是PNPase。我们的数据进一步证明，PNPase以序列特异性方式与DNA结合。这些数据表明，PNPase除了在mRNA降解中已知的作用外，可能还具有以前未被认识到的与DNA相关的功能。
