3UAX

Crystal structure of adenosine phosphorylase from Bacillus cereus complexed with inosine

3UAX の概要

• エントリーDOI: 10.2210/pdb3uax/pdb
• 関連するPDBエントリー: 3UAV 3UAW 3UAY 3UAZ
• 分子名称: Purine nucleoside phosphorylase deoD-type, INOSINE, SULFATE ION, ... (5 entities in total)
• 機能のキーワード: necleoside phosphorylase i (np-i) family, transferase
• 由来する生物種: Bacillus cereus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 26156.76

構造登録者

Dessanti, P.,Zhang, Y.,Allegrini, S.,Tozzi, M.G.,Sgarrella, F.,Ealick, S.E. (登録日: 2011-10-22, 公開日: 2012-02-29, 最終更新日: 2023-09-13)

主引用文献

Dessanti, P.,Zhang, Y.,Allegrini, S.,Tozzi, M.G.,Sgarrella, F.,Ealick, S.E.
Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase.
Acta Crystallogr.,Sect.D, 68:239-248, 2012

PubMed Abstract: Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2'-deoxy)nucleosides, generating the corresponding free base and (2'-deoxy)-ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2-1.4 Å). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

PubMed: 22349225
DOI: 10.1107/S090744491200073X

実験手法

X-RAY DIFFRACTION (1.2 Å)