title: Crystal structure of the rice branching enzyme I (BEI) in complex with maltopentaose.
abstract: Starch branching enzyme (SBE) catalyzes the cleavage of α-1,4-linkages and the subsequent transfer of α-1,4 glucan to form an α-1,6 branch point in amylopectin. We determined the crystal structure of the rice branching enzyme I (BEI) in complex with maltopentaose at a resolution of 2.2Å. Maltopentaose bound to a hydrophobic pocket formed by the N-terminal helix, carbohydrate-binding module 48 (CBM48), and α-amylase domain. In addition, glucose moieties could be observed at molecular surfaces on the N-terminal helix (α2) and CBM48. Amino acid residues involved in the carbohydrate bindings are highly conserved in other SBEs, suggesting their generally conserved role in substrate binding for SBEs.
authors: Laboratory of Structural Biology, Graduate School of Systems Life Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan.
authors: Kimiko
authors: K
authors: Chaen
authors: Junji
authors: J
authors: Noguchi
authors: Toshiro
authors: T
authors: Omori
authors: Yoshimitsu
authors: Y
authors: Kakuta
authors: Makoto
authors: M
authors: Kimura
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000737:chemistry*; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D012275:Oryza / Q000201:enzymology*; D017433:Protein Structure, Secondary
chemical_list: D009844:Oligosaccharides; C019193:maltopentaose; D015061:1,4-alpha-Glucan Branching Enzyme