不同来源的β-螺旋桨植酸酶使植酸去磷酸化的途径。

Pathway of phytate dephosphorylation by beta-propeller phytases of different origins.

作者信息

Greiner Ralf, Lim Boon L, Cheng Chiwai, Carlsson Nils-Gunnar

机构信息

Centre for Molecular Biology, Federal Research Centre for Nutrition and Food, Haid-und-Neu-Strasse 9, Karlsruhe, Germany.

出版信息

Can J Microbiol. 2007 Apr;53(4):488-95. doi: 10.1139/W07-015.

DOI:10.1139/W07-015

PMID:17612603

Abstract

Using a combination of high-performance ion chromatography analysis and kinetic studies, the pathway of myo-inositol hexakisphosphate dephosphorylation by the beta-propeller phytase of Shewanella oneidensis was established, which was then compared with that of Bacillus subtilis 168, Bacillus amyloliquefaciens ATCC 15841, and B. amyloliquefaciens 45 beta-propeller phytases. The data demonstrate that all of these beta-propeller phytases dephosphorylate myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via d-Ins(1,2,4,5,6)P5, Ins(2,4,5,6)P4 to finally Ins(2,4,6)P3. Thus, the beta-propeller phytases prefer the hydrolysis of every second phosphate over that of adjacent ones. This finding does not support previous phytate degradation models proposed by J. Kerovuo, J. Rouvinen, and F. Hatzack (2000. Biochem. J. 352: 623-628) and R. Greiner, A. Farouk, M. Larsson Alminger, and N.G. Carlsson (2002. Can. J. Microbiol. 48: 986-994), but seems to fit with the structural model given by S. Shin, N.C. Ha, B.C. Oh, T.K. Oh, and B.H. Oh (2001. Structure, 9: 851-858).

摘要

通过结合高效离子色谱分析和动力学研究，确定了希瓦氏菌β-螺旋桨植酸酶使肌醇六磷酸去磷酸化的途径，然后将其与枯草芽孢杆菌168、解淀粉芽孢杆菌ATCC 15841和解淀粉芽孢杆菌45的β-螺旋桨植酸酶的途径进行比较。数据表明，所有这些β-螺旋桨植酸酶通过依次经由d-Ins(1,2,4,5,6)P5、Ins(2,4,5,6)P4去除磷酸基团，最终生成Ins(2,4,6)P3，以立体特异性方式使肌醇六磷酸去磷酸化。因此，β-螺旋桨植酸酶更倾向于水解每隔一个的磷酸基团，而不是相邻的磷酸基团。这一发现不支持J. Kerovuo、J. Rouvinen和F. Hatzack（2000年，《生物化学杂志》352卷：623 - 628页）以及R. Greiner、A. Farouk、M. Larsson Alminger和N.G. Carlsson（2002年，《加拿大微生物学杂志》48卷：986 - 994页）先前提出的植酸盐降解模型，但似乎与S. Shin、N.C. Ha、B.C. Oh、T.K. Oh和B.H. Oh（2001年，《结构》9卷：851 - 858页）给出的结构模型相符。