当前位置： SCI文献检索 > JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS期刊下所有文献 > The comparative analysis of the properties and structures of purine nucleoside phosphorylases from thermophilic bacterium Thermus thermophilus HB27.

The comparative analysis of the properties and structures of purine nucleoside phosphorylases from thermophilic bacterium Thermus thermophilus HB27.

Abstract：

:Two recombinant purine nucleoside phosphorylases from thermophilic bacterium Thermus thermophilus HB27 encoded by genes TT_C1070 (TthPNPI) and TT_C0194 (TthPNPII) were purified and characterized. The comparative analysis of their sequences, molecular weight, enzymes specificity and kinetics of the catalyzed reaction were realized. As a result, it was determined that the TthPNPI is specific to guanosine while the TthPNPII to adenosine. According to the results of the size exclusion chromatography and SAXS study both enzymes are hexameric molecules. Based on the sequence alignment with homologous purine nucleoside phosphorylases (PNPs), Asn was identified as a purine base recognizing residue in the active site of TthPNPI and Asp in TthPNPII. The three-dimensional structure of TthPNPII was solved at 2.5 Å resolution by molecular replacement method using crystals grown in microgravity. Position of phosphate in the active site cavity is located. The possible arrangement of adenosine and guanosine in TthPNPII active site cavity is considered using superposition with the structures of homologous trimeric and hexameric PNPs complexed with corresponding substrates. The peculiarities of oligomeric structure of TthPNPII in comparison with homologous PNPs are described. It is shown that two trimeric molecules of TthPNPII in the asymmetric part of the unit cell are connected by three two-fold axis into a hexamer with 32-point symmetry. This type of hexameric structure of PNP is found for the first time. The interface area between the subunits in trimeric molecule and between the trimers in TthPNPII hexamer is described. Communicated by Ramaswamy H. Sarma.

journal_name

J Biomol Struct Dyn

journal_title

Journal of biomolecular structure & dynamics

authors

Timofeev VI,Fateev IV,Kostromina MA,Abramchik YA,Konstantinova ID,Volkov VV,Lykoshin DD,Mikheeva OO,Muravieva TI,Esipov RS,Kuranova IP

doi

10.1080/07391102.2020.1848628

subject

Has Abstract

pub_date

2020-11-23 00:00:00

pages

1-16

eissn

0739-1102

issn

1538-0254

pub_type

杂志文章

在线工具

The comparative analysis of the properties and structures of purine nucleoside phosphorylases from thermophilic bacterium Thermus thermophilus HB27.