Structure of the AliC GH13 α−amylase from Alicyclobacillus sp, reveals accommodation of starch branching points in the α−amylase family

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review



  • Author: Agirre, Jon

    University of York, United Kingdom

  • Author: Moroz, Olga V.

    University of York, United Kingdom

  • Author: Meier, Sebastian

    Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800, Kgs. Lyngby, Denmark

  • Author: Braak, Jesper

    Novozymes A/S, Denmark

  • Author: Munch, Astrid

    Technical University of Denmark

  • Author: Hoff, Tine

    Novozymes A/S, Denmark

  • Author: Anderson, Carsten

    Novozymes A/S, Denmark

  • Author: Wilson, Keith S.

    University of York, Denmark

  • Author: Davies, Gideon J.

    University of York

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α−amylases are glycoside hydrolases that break the α−1,4 bonds in starch and related glycans. The degradation of starch is rendered difficult by varying degrees of α−1,6 branch points and their possible accommodation within the active centre of α−amylase enzymes. Given the myriad industrial uses for starch and thus also for α−amylase-catalysed starch degradation and modification, there is considerable interest in how different α−amylases might accommodate these branches thus impacting on the potential limit dextrins and societal applications. Here, we sought to probe the branch-point accommodation of the Alicyclobacillus sp. CAZy family GH13 α−amylase, prompted by our observation of a molecule of glucose in the position that may represent a branch point in an acarbose complex solved at 2.1 Å resolution. Limit digest analysis, by 2D NMR, using both pullulan (a regular linear polysaccharide of α−1,4, α−1,4, α−1,6 repeating trisaccharides) and amylopectin starch showed how the Alicyclobacillus sp enzyme could accept α−1,6 branches in, at least, -2, +1 and +2 subsites consistent with 3-D structures with glucosyl moieties in +1 and +2 subsites and the solvent exposure of the -2 6-hydroxyl group. Together the work provides a rare insight into branch point acceptance in these industrial catalysts.
Original languageEnglish
JournalActa crystallographica Section D: Structural biology
Issue number1
Pages (from-to)1-7
Number of pages7
Publication statusPublished - 2019
CitationsWeb of Science® Times Cited: No match on DOI

    Research areas

  • AliC GH13 α-analyse, Starch brancing points, Glycoside hydrolases, Pullulan, Carbohydrate-active enzymes, Alicyclobacillus

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