9US5

Domain N deletion mutant of Klebsiella pneumoniae maltohexaose-producing alpha-amylase in complex with maltohexaose

Summary for 9US5

• Entry DOI: 10.2210/pdb9us5/pdb
• Related PRD ID: PRD_900010
• Descriptor: Maltohexaose-producing amylase, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: glycosyl hydrolase family 13, hydrolase
• Biological source: Klebsiella pneumoniae
• Total number of polymer chains: 1
• Total formula weight: 64543.75

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 (2.66 Å)