5n7j
From Proteopedia
Crystal structure of Neisseria polysaccharea amylosucrase mutant efficient for the synthesis of controlled size maltooligosaccharides
Structural highlights
FunctionAMYS_NEIPO Catalyzes the synthesis of alpha-glucan from sucrose. Catalyzes, in addition, sucrose hydrolysis, maltose and maltotriose synthesis by successive transfers of the glucosyl moiety of sucrose onto the released glucose, and finally turanose and trehalulose synthesis, these two sucrose isomers being obtained by glucosyl transfer onto fructose.[1] Publication Abstract from PubMedAmylosucrase from Neisseria polysaccharea naturally catalyzes the synthesis of alpha-1,4 glucans from sucrose. The product profile is quite polydisperse, ranging from soluble chains called maltooligosaccharides to high-molecular weight insoluble amylose. This enzyme was recently subjected to engineering of its active site to enable recognition of non-natural acceptor substrates. Libraries of variants were constructed and screened on sucrose, allowing the identification of a mutant that showed a 6-fold enhanced activity toward sucrose compared to the wild-type enzyme. Furthermore, its product profile was unprecedented, as only soluble maltooligosaccharides of controlled size chains (2<DP<21) with a narrow polydispersity were observed. This variant, containing 9 mutations in the active site, was characterized at both biochemical and structural levels. Its x-ray structure was determined and further investigated by molecular dynamics to understand the molecular origins of its higher activity on sucrose and higher production of small maltooligosaccharides, with a totally abolished insoluble glucan synthesis. Engineering of anp efficient mutant of Neisseria polysaccharea amylosucrase for the synthesis of controlled size maltooligosaccharides.,Verges A, Barbe S, Cambon E, Moulis C, Tranier S, Remaud-Simeon M, Andre I Carbohydr Polym. 2017 Oct 1;173:403-411. doi: 10.1016/j.carbpol.2017.06.011. Epub, 2017 Jun 7. PMID:28732882[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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