Complete subsite mapping of a "loopful" GH19 chitinase from rye seeds based on its crystal structure. Issue 16 (18th July 2013)

• Record Type: Journal Article
• Authors: Ohnuma, Takayuki; Umemoto, Naoyuki; Kondo, Kaori; Numata, Tomoyuki; Fukamizo, Tamo
• Is Part Of: FEBS letters. Volume 587:Issue 16(2013)
• Page Start: 2691
• Page End: 2697
• Publication Date: 2013-07-18
• Subjects: GlcNAc -- 2-acetamido-2-deoxy-β-d-glucopyranose -- (GlcNAc)n -- β-1, 4-linked oligosaccharide of GlcNAc with a polymerization degree of n -- RSC-c -- wild type GH19 chitinase from rye seeds -- RSC-c-E67Q/W72A -- a double mutant RSC-c, in which Glu67 and Trp72 are mutated to glutamine and alanine, respectively -- 2 × (GlcNAc)4 -- two molecules of (GlcNAc)4 -- MD -- molecular dynamics -- Crystal structure -- GH19 chitinase -- Rye seed -- Chitin oligosaccharide -- Domain motion; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1016/j.febslet.2013.07.008
• Languages: English
• ISSNs: 0014-5793

Abstract

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. Abstract : Crystallographic analysis of GH‐19 chitinase‐(GlcNAc)4 complex revealed eight subsites. Crystal structures of liganded and unliganded forms of the enzyme suggested the domain motion. Among the eight subsites, the GlcNAc residues at +1, −1, and −2 are strongly recognized by the enzyme.