Crystal structure of α-amylase from Oryza sativa: molecular insights into enzyme activity and thermostability

Autor: Ochiai, Akihito, Sugai, Hiroshi, Harada, Kazuki, Tanaka, Seiya, Ishiyama, Yohei, Ito, Kosuke, Tanaka, Takaaki, Uchiumi, Toshio, Taniguchi, Masayuki, Mitsui, Toshiaki
Zdroj: Bioscience, Biotechnology, and Biochemistry; June 2014, Vol. 78 Issue: 6 p989-997, 9p
Abstrakt: AmyI-1 is an α-amylase from Oryza sativa(rice) and plays a crucial role in degrading starch in various tissues and at various growth stages. This enzyme is a glycoprotein with an N-glycosylated carbohydrate chain, a unique characteristic among plant α-amylases. In this study, we report the first crystal structure of AmyI-1 at 2.2-Å resolution. The structure consists of a typical (β/α)8-barrel, which is well-conserved among most α-amylases in the glycoside hydrolase family-13. Structural superimposition indicated small variations in the catalytic domain and carbohydrate-binding sites between AmyI-1 and barley α-amylases. By contrast, regions around the N-linked glycosylation sites displayed lower conservation of amino acid residues, including Asn-263, Asn-265, Thr-307, Asn-342, Pro-373, and Ala-374 in AmyI-1, which are not conserved in barley α-amylases, suggesting that these residues may contribute to the construction of the structure of glycosylated AmyI-1. These results increase the depths of our understanding of the biological functions of AmyI-1.
Databáze: Supplemental Index