2OWC

Structure of a covalent intermediate in Thermus thermophilus amylomaltase

Summary for 2OWC

• Entry DOI: 10.2210/pdb2owc/pdb
• Related PRD ID: PRD_900110
• Descriptor: 4-alpha-glucanotransferase, 4,6-dideoxy-4-{[(1S,4R,5S,6S)-4,5,6-trihydroxy-3-(hydroxymethyl)cyclohex-2-en-1-yl]amino}-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, GLYCEROL, ... (5 entities in total)
• Functional Keywords: amylomaltase, alpha-amylase, beta-alpha-barrel, glycosyl-enzyme, transferase
• Biological source: Thermus thermophilus
• Total number of polymer chains: 1
• Total formula weight: 58205.84

Authors

Barends, T.R.M.,Bultema, J.B.,Kaper, T.,van der Maarel, M.J.E.C.,Dijkhuizen, L.,Dijkstra, B.W. (deposition date: 2007-02-16, release date: 2007-04-03, Last modification date: 2023-11-15)

Primary citation

Barends, T.R.,Bultema, J.B.,Kaper, T.,van der Maarel, M.J.,Dijkhuizen, L.,Dijkstra, B.W.
Three-way stabilization of the covalent intermediate in amylomaltase, an alpha-amylase-like transglycosylase.
J.Biol.Chem., 282:17242-17249, 2007

PubMed Abstract: Amylomaltases are glycosyl hydrolases belonging to glycoside hydrolase family 77 that are capable of the synthesis of large cyclic glucans and the disproportionation of oligosaccharides. Using protein crystallography, we have generated a flip book movie of the amylomaltase catalytic cycle in atomic detail. The structures include a covalent glycosyl enzyme intermediate and a covalent intermediate in complex with an analogue of a co-substrate and show how the structures of both enzyme and substrate respond to the changes required by the catalytic cycle as it proceeds. Notably, the catalytic nucleophile changes conformation dramatically during the reaction. Also, Gln-256 on the 250s loop is involved in orienting the substrate in the +1 site. The absence of a suitable base in the covalent intermediate structure explains the low hydrolysis activity.

PubMed: 17420245
DOI: 10.1074/jbc.M701444200

Experimental method

X-RAY DIFFRACTION (2.05 Å)