title: Complete subsite mapping of a "loopful" GH19 chitinase from rye seeds based on its crystal structure.
abstract: Crystallographic analysis of a mutated form of "loopful" GH19 chitinase from rye seeds a double mutant RSC-c, in which Glu67 and Trp72 are mutated to glutamine and alanine, respectively, (RSC-c-E67Q/W72A) in complex with chitin tetrasaccharide (GlcNAc)₄ revealed that the entire substrate-binding cleft was completely occupied with the sugar residues of two (GlcNAc)₄ molecules. One (GlcNAc)₄ molecule bound to subsites -4 to -1, while the other bound to subsites +1 to +4. Comparisons of the main chain conformation between liganded RSC-c-E67Q/W72A and unliganded wild type RSC-c suggested domain motion essential for catalysis. This is the first report on the complete subsite mapping of GH19 chitinase.
authors.affiliation: Department of Advanced Bioscience, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ohnuma
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Umemoto
authors.forename: Kaori
authors.initials: K
authors.lastname: Kondo
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Numata
authors.forename: Tamo
authors.initials: T
authors.lastname: Fukamizo
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry; D020134:Catalytic Domain; D002688:Chitinases / Q000737:chemistry* / Q000235:genetics; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D008024:Ligands; D008958:Models, Molecular; D009154:Mutation; D009844:Oligosaccharides / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics; D011485:Protein Binding; D012434:Secale / Q000201:enzymology*; D012639:Seeds / Q000378:metabolism
chemical_list: D008024:Ligands; D009844:Oligosaccharides; D010940:Plant Proteins; D002688:Chitinases; C583899:GH19 chitinase, rye; D000117:Acetylglucosamine
keywords: (GlcNAc)(n); 2-acetamido-2-deoxy-β-d-glucopyranose; 2×(GlcNAc)(4); Chitin oligosaccharide; Crystal structure; Domain motion; GH19 chitinase; GlcNAc; MD; RSC-c; RSC-c-E67Q/W72A; Rye seed; a double mutant RSC-c, in which Glu67 and Trp72 are mutated to glutamine and alanine, respectively; molecular dynamics; two molecules of (GlcNAc)(4); wild type GH19 chitinase from rye seeds; β-1,4-linked oligosaccharide of GlcNAc with a polymerization degree of n