Eliminating hydrolytic activity without affecting the transglycosylation of a GH1 β-glucosidase

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Abstract

Unveiling the determinants for transferase and hydrolase activity in glycoside hydrolases would allow using their vast diversity for creating novel transglycosylases, thereby unlocking an extensive toolbox for carbohydrate chemists. Three different amino acid substitutions at position 220 of a GH1 β-glucosidase from Thermotoga neapolitana caused an increase of the ratio of transglycosylation to hydrolysis (rs/rh) from 0.33 to 1.45–2.71. Further increase in rs/rh was achieved by modulation of pH of the reaction medium. The wild-type enzyme had a pH optimum for both hydrolysis and transglycosylation around 6 and reduced activity at higher pH. Interestingly, the mutants had constant transglycosylation activity over a broad pH range (5–10), while the hydrolytic activity was largely eliminated at pH 10. The results demonstrate that a combination of protein engineering and medium engineering can be used to eliminate the hydrolytic activity without affecting the transglycosylation activity of a glycoside hydrolase. The underlying factors for this success are pursued, and perturbations of the catalytic acid/base in combination with flexibility are shown to be important factors.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Biokemi och molekylärbiologi
  • Biokatalys och enzymteknik

Nyckelord

Originalspråkengelska
Sidor (från-till)1121-1131
TidskriftApplied Microbiology and Biotechnology
Volym101
Utgåva nummer3
Tidigt onlinedatum2016 sep 27
StatusPublished - 2017 feb
PublikationskategoriForskning
Peer review utfördJa