1L7K

x-ray structure of galactose mutarotase from Lactococcus lactis complexed with galactose

1L7K の概要

• エントリーDOI: 10.2210/pdb1l7k/pdb
• 分子名称: galactose mutarotase, alpha-D-galactopyranose, SODIUM ION, ... (4 entities in total)
• 機能のキーワード: mutarotase, epimerase, galactose metabolism, isomerase
• 由来する生物種: Lactococcus lactis
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 77629.22

構造登録者

Holden, H.M.,Thoden, J.B. (登録日: 2002-03-15, 公開日: 2002-04-24, 最終更新日: 2023-08-16)

主引用文献

Thoden, J.B.,Holden, H.M.
High resolution X-ray structure of galactose mutarotase from Lactococcus lactis.
J.Biol.Chem., 277:20854-20861, 2002

PubMed Abstract: Galactose mutarotase plays a key role in normal galactose metabolism by catalyzing the interconversion of beta-D-galactose and alpha-D-galactose. Here we describe the three-dimensional architecture of galactose mutarotase from Lactococcus lactis determined to 1.9-A resolution. Each subunit of the dimeric enzyme displays a distinctive beta-sandwich motif. This tertiary structural element was first identified in beta-galactosidase and subsequently observed in copper amine oxidase, hyaluronate lyase, chondroitinase, and maltose phosphorylase. Two cis-peptides are found in each subunit, namely Pro(67) and Lys(136). The active site is positioned in a rather open cleft, and the electron density corresponding to the bound galactose unequivocally demonstrates that both anomers of the substrate are present in the crystalline enzyme. Those residues responsible for anchoring the sugar to the protein include Arg(71), His(96), His(170), Asp(243), and Glu(304). Both His(96) and His(170) are strictly conserved among mutarotase amino acid sequences determined thus far. The imidazole nitrogens of these residues are located within hydrogen bonding distance to the C-5 oxygen of galactose. Strikingly, the carboxylate group of Glu(304) is situated at approximately 2.7 A from the 1'-hydroxyl group of galactose, thereby suggesting its possible role as a general acid/base group.

PubMed: 11907040
DOI: 10.1074/jbc.M111778200

実験手法

X-RAY DIFFRACTION (1.95 Å)