9US4

Klebsiella pneumoniae maltohexaose-producing alpha-amylase in complex with acarbose

Summary for 9US4

• Entry DOI: 10.2210/pdb9us4/pdb
• Related PRD ID: PRD_900007 PRD_900022 PRD_900110
• Descriptor: Maltohexaose-producing amylase, 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-(1-4)-beta-D-glucopyranose, 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-(1-4)-alpha-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: glycosyl hydrolase family 13, hydrolase
• Biological source: Klebsiella pneumoniae
• Total number of polymer chains: 2
• Total formula weight: 153059.27

Authors

Fujimoto, Z.,Kishine, N.,Momma, M. (deposition date: 2025-05-01, release date: 2025-07-09)

Primary citation

Fujimoto, Z.,Kishine, N.,Momma, M.
Crystal structure of Klebsiella pneumoniae maltohexaose-producing alpha-amylase.
J.Biochem., 2025

PubMed Abstract: The α-amylase from Klebsiella pneumoniae (KpAmy13), which belongs to glycoside hydrolase family 13 subfamily 19, produces maltohexaose as an initial product when acting on starch and has been characterized as a maltohexaose-producing α-amylase. The crystal structure of KpAmy13 was determined at a resolution of 1.9 Å, revealing the structures of all its domains: N, A, B, and C. Domain N resembles the starch-binding domain known as carbohydrate-binding module family 69, found in α-glucan-related proteins. Although domain N does not conserve the starch-binding residues observed in other proteins, it has several hydrophobic residues on its surface, which might be involved in promoting catalysis. The catalytic cleft is located at the bottom of a circular depression. The domain N-truncated mutant of KpAmy13 in complex with maltohexaose showed that its non-reducing end glucose docks at subsite -6. The long and complex structure of domain B contributes to forming a cleft of the right size for six glucose moieties, demonstrating the exo-acting mechanism.

PubMed: 40576559
DOI: 10.1093/jb/mvaf034

Experimental method

X-RAY DIFFRACTION (1.95 Å)