Bermúdez-Cruz Rosa Ma, García-Mena Jaime, Montañez Cecilia
Departamento de Genética y Biología Molecular, Centro de Investigación y Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000, Mexico, Mexico.
Biochimie. 2002 Apr;84(4):321-8. doi: 10.1016/s0300-9084(02)01385-8.
Polynucleotide phosphorylase (PNPase, polyribonucleotide nucleotidyltransferase, EC 2.7.7.8) is a multifunctional protein, with a 3'-5' processive exoribonuclease, a Pi exchange, an RNA polymerase and an autoregulatory activity. The interaction between this enzyme and the mRNA target is crucial for its activities. In the present study, we characterized the interaction of PNPase with its mRNA regulatory region and ssRNA, as well as with ssDNA and dsDNA by determining K(d). Our results indicate that PNPase has high affinity for its mRNA, ssRNA and for ssDNA (K(d) approximately 10-20 nM). However, this enzyme exhibits a lower affinity for dsDNA (K(d) approximately 200-1400 nM). Possible implications of these results on the molecular mechanisms by which PNPase is regulated and degrades mRNA are discussed.
多核苷酸磷酸化酶（PNPase，聚核糖核苷酸核苷酸转移酶，EC 2.7.7.8）是一种多功能蛋白质，具有3'-5'连续外切核糖核酸酶、磷酸交换、RNA聚合酶和自调节活性。该酶与mRNA靶标的相互作用对其活性至关重要。在本研究中，我们通过测定解离常数（K(d)）来表征PNPase与其mRNA调控区域、单链RNA以及单链DNA和双链DNA的相互作用。我们的结果表明，PNPase对其mRNA、单链RNA和单链DNA具有高亲和力（K(d)约为10 - 20 nM）。然而，该酶对双链DNA的亲和力较低（K(d)约为200 - 1400 nM）。本文讨论了这些结果对PNPase调控和降解mRNA的分子机制的可能影响。
