1M7X

The X-ray Crystallographic Structure of Branching Enzyme

1M7X の概要

• エントリーDOI: 10.2210/pdb1m7x/pdb
• 分子名称: 1,4-alpha-glucan Branching Enzyme (2 entities in total)
• 機能のキーワード: alpha/beta barrel, beta sandwich, transferase
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 287180.94

構造登録者

Abad, M.C.,Binderup, K.,Rios-Steiner, J.,Arni, R.K.,Preiss, J.,Geiger, J.H. (登録日: 2002-07-23, 公開日: 2002-09-18, 最終更新日: 2024-05-22)

主引用文献

Abad, M.C.,Binderup, K.,Rios-Steiner, J.,Arni, R.K.,Preiss, J.,Geiger, J.H.
The X-ray crystallographic structure of Escherichia coli branching enzyme
J.Biol.Chem., 277:42164-42170, 2002

PubMed Abstract: Branching enzyme catalyzes the formation of alpha-1,6 branch points in either glycogen or starch. We report the 2.3-A crystal structure of glycogen branching enzyme from Escherichia coli. The enzyme consists of three major domains, an NH(2)-terminal seven-stranded beta-sandwich domain, a COOH-terminal domain, and a central alpha/beta-barrel domain containing the enzyme active site. While the central domain is similar to that of all the other amylase family enzymes, branching enzyme shares the structure of all three domains only with isoamylase. Oligosaccharide binding was modeled for branching enzyme using the enzyme-oligosaccharide complex structures of various alpha-amylases and cyclodextrin glucanotransferase and residues were implicated in oligosaccharide binding. While most of the oligosaccharides modeled well in the branching enzyme structure, an approximate 50 degrees rotation between two of the glucose units was required to avoid steric clashes with Trp(298) of branching enzyme. A similar rotation was observed in the mammalian alpha-amylase structure caused by an equivalent tryptophan residue in this structure. It appears that there are two binding modes for oligosaccharides in these structures depending on the identity and location of this aromatic residue.

PubMed: 12196524
DOI: 10.1074/jbc.M205746200

実験手法

X-RAY DIFFRACTION (2.3 Å)