A single mutation in cyclodextrin glycosyltransferase from Paenibacillus barengoltzii changes cyclodextrin and maltooligosaccharides production

CAMINATA LANDRIEL, SOLEDAD; BERENGUER, J.; COSTA HERNÁN; SANCHES COSTA, MERCEDES; HIDALGO, AURELIO; SANCHES COSTA, MERCEDES; HIDALGO, AURELIO; CASTILLO DE LAS MERCEDES JULIETA; TABOGA, OSCAR ALBERTO; FERRAROTTI SUSANA ALICIA; CASTILLO DE LAS MERCEDES JULIETA; TABOGA, OSCAR ALBERTO; FERRAROTTI SUSANA ALICIA; CAMINATA LANDRIEL, SOLEDAD; BERENGUER, J.; COSTA HERNÁN

PROTEIN ENGINEERING DESIGN & SELECTION

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2019 p. 1 - 9

1741-0126

Cyclodextrin glycosyltransferases (CGTases) are bacterial enzymes thatcatalyze starch conversion into cyclodextrins, which have severalbiotechnological applications including solubilization of hydrophobiccompounds, masking of unpleasant odors and flavors in pharmaceuticalpreparations, and removal of cholesterol from food. Additionally, CGTasesproduce maltooligosaccharides, which are linear molecules with potentialbenefits for human health. Current research efforts are concentrated in thedevelopment of engineered enzymes with improved yield and/or particular productspecificity. In this work we analyzed the role of four residues of theCGTase from Paenibacillus barengoltziias determinants of product specificity. Single mutations were introduced in theCGTase-encoding gene to obtain mutants A137V, A144V, L280A and M329I and theactivity of recombinant proteins was evaluated. The residue at position 137proved to be relevant for CGTase activity. Molecular dynamics studies demonstratedadditionally that mutation A137V produces a perturbation in the catalytic siteof the CGTase, which correlates with a 10-fold reduction in its catalyticefficiency. Moreover, this mutant showed increased production of maltooligosaccharideswith a high degree of polymerization, mostly maltopentaose to maltoheptaose.Our results highlight the role of residue 137 as a determinant of productspecificity in this CGTase and may be applied to the rational design of saccharide-producingenzymes.