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Journal Articles ACS Catalysis Year : 2018

Structural Dynamics and Catalytic Properties of a Multimodular Xanthanase

Dorotea R. Seura
  • Function : Author
Lars Anderson
Santhosh M. Vasu
  • Function : Author
Vasudeva P. Rao
  • Function : Author
Lars Giger
  • Function : Author
Rune Nygaard Monrad
  • Function : Author
Allan Svendsen
  • Function : Author
Jens Nielsen

Abstract

The precise catalytic strategies used for the breakdown of the complex bacterial polysaccharide xanthan, an increasingly frequent component of processed human foodstuffs, have remained a mystery. Here, we present characterization of an endo-xanthanase from Paenibacillus nanensis. We show that it is a CAZy family 9 glycoside hydrolase (GH9) responsible for the hydrolysis of the xanthan backbone capable of generating tetrameric xanthan oligosaccharides from polysaccharide lyase family 8 (PL8) xanthan lyase-treated xanthan. Three-dimensional structure determination reveals a complex multimodular enzyme in which a catalytic (alpha/alpha)(6) barrel is flanked by an N-terminal "immunoglobulin-like" (Ig-like) domain (frequently found in GH9 enzymes) and by four additional C-terminal all beta-sheet domains that have very few homologues in sequence databases and at least one of which functions as a new xanthan-binding domain, now termed CBM84. The solution-phase conformation and dynamics of the enzyme in the native calcium-bound state and in the absence of calcium were probed experimentally by hydrogen/deuterium exchange mass spectrometry. Measured conformational dynamics were used to guide the protein engineering of enzyme variants with increased stability in the absence of calcium; a property of interest for the potential use of the enzyme in cleaning detergents. The ability of hydrogen/deuterium exchange mass spectrometry to pinpoint dynamic regions of a protein under stress (e.g., removal of calcium ions) makes this technology a strong tool for improving protein catalyst properties by informed engineering.

Dates and versions

hal-02621066 , version 1 (26-05-2020)

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Olga V. Moroz, Pernille F. Jensen, Sean P. Mcdonald, Nicholas Mcgregor, Elena Blagova, et al.. Structural Dynamics and Catalytic Properties of a Multimodular Xanthanase. ACS Catalysis, 2018, 8 (7), pp.6021-6034. ⟨10.1021/acscatal.8b00666⟩. ⟨hal-02621066⟩
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