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Product-oriented chemical surface modification of a levansucrase (SacB) via an ene-type reaction.

ABSTRACT: Carbohydrate processing enzymes are sophisticated tools of living systems that have evolved to execute specific reactions on sugars. Here we present for the first time the site-selective chemical modification of exposed tyrosine residues in SacB, a levansucrase from Bacillus megaterium (Bm-LS) for enzyme engineering purposes via an ene-type reaction. Bm-LS is unable to sustain the synthesis of high molecular weight (HMW) levan (a fructose polymer) due to protein-oligosaccharide dissociation events occurring at an early stage during polymer elongation. We switched the catalyst from levan-like oligosaccharide synthesis to the efficient production of a HMW fructan polymer through the covalent addition of a flexible chemical side-chain that fluctuates over the central binding cavity of the enzyme preventing premature oligosaccharide disengagement.

SUBMITTER: Ortiz-Soto ME

PROVIDER: S-EPMC6009436 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Product-oriented chemical surface modification of a levansucrase (SacB) via an ene-type reaction.

Ortiz-Soto Maria Elena ME Ertl Julia J Mut Jürgen J Adelmann Juliane J Le Thien Anh TA Shan Junwen J Teßmar Jörg J Schlosser Andreas A Engels Bernd B Seibel Jürgen J

Chemical science 20180522 24

Carbohydrate processing enzymes are sophisticated tools of living systems that have evolved to execute specific reactions on sugars. Here we present for the first time the site-selective chemical modification of exposed tyrosine residues in SacB, a levansucrase from Bacillus megaterium (Bm-LS) for enzyme engineering purposes via an ene-type reaction. Bm-LS is unable to sustain the synthesis of high molecular weight (HMW) levan (a fructose polymer) due to protein-oligo ...[more]

PMID: 30009003

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