1VAH

Crystal structure of the pig pancreatic-amylase complexed with r-nitrophenyl-a-D-maltoside

1VAH の概要

• エントリーDOI: 10.2210/pdb1vah/pdb
• 関連するPDBエントリー: 1JFH 1UA3
• 分子名称: Alpha-amylase, pancreatic, CHLORIDE ION, CALCIUM ION, ... (5 entities in total)
• 機能のキーワード: beta-alpha-barrels, hydrolase
• 由来する生物種: Sus scrofa (pig)
• 細胞内の位置: Secreted, extracellular space: P00690
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 55689.48

構造登録者

Zhuo, H.,Payan, F.,Qian, M. (登録日: 2004-02-17, 公開日: 2005-04-26, 最終更新日: 2024-11-20)

主引用文献

Zhuo, H.,Payan, F.,Qian, M.
Crystal structure of the pig pancreatic alpha-amylase complexed with rho-nitrophenyl-alpha-D-maltoside-flexibility in the active site
Protein J., 23:379-387, 2004

PubMed Abstract: The X-ray structure analysis of a crystal of pig pancreatic alpha-amylase soaked with a rho-nitrophenyl-alpha-D-maltoside (pNPG2) substrate showed a pattern of electron density corresponding to the binding of a rho-nitrophenol unit at subsite -2 of the active site. Binding of the product to subsite -2 after hydrolysis of the pNPG2 molecules, may explain the low catalytic efficiency of the hydrolysis of pNPG2 by PPA. Except a small movement of the segment from residues 304-305 the typical conformational changes of the "flexible loop" (303-309), that constitutes the surface edge of the substrate binding cleft, were not observed in the present complex structure. This result supports the hypothesis that significant movement of the loop may depend on aglycone site being filled (Payan and Qian, J. Protein Chen. 22: 275, 2003). Structural analyses have shown that pancreatic alpha-amylases undergo an induced conformational change of the catalytic residue Asp300 upon substrate binding; in the present complex the catalytic residue is observed in its unliganded orientation. The results suggest that the induced reorientation is likely due to the presence of a sugar unit at subsite -1 and not linked to the closure of the flexible surface loop. The crystal structure was refined at 2.4 A resolution to an R factor of 17.55% (Rfree factor of 23.32%).

PubMed: 15517985
DOI: 10.1023/B:JOPC.0000039552.94529.95

実験手法

X-RAY DIFFRACTION (2.4 Å)