Enzymatic Synthesis of Galactosylated Serine/Threonine Derivatives by β-Galactosidase from Escherichia coli

International Journal of Molecular Sciences

Sooyoun Seo²  Joseph Rebehmed¹  Alexandre G. de Brevern¹  Salwa Karboune²  Patricia Berninsone³ 

[1] INSERM UMR_S 1134, Dynamique des Structures et Interactions des Macromolécules Biologiques (DSIMB), University Paris Diderot, Sorbonne Paris Cité, INTS, Laboratory of excellence, GR-Ex, 6, rue Alexandre Cabanel, 75739 Paris Cedex 15, France; E-Mails:;Department of Food Science and Agricultural Chemistry, McGill University, 21,111 Lakeshore, Ste Anne de Bellevue, QC H9X-3V9, Canada; E-Mail:;Department of Food Science and Agricultural Chemistry, McGill University, 21,111 Lakeshore, Ste Anne de Bellevue, QC H9X-3V9, Canada; E-Mail

关键词: β-galactosidase;    transgalactosylation;    serine/threonine derivatives;    molecular docking;    binding affinities;    galactosyl acceptor;   

DOI  :  10.3390/ijms160613714

来源: mdpi

【 摘 要 】

The transgalactosylations of serine/threonine derivatives were investigated using β-galactosidase from Escherichia coli as biocatalyst. Using ortho-nitrophenyl-β-d-galactoside as donor, the highest bioconversion yield of transgalactosylated N-carboxy benzyl l-serine benzyl ester (23.2%) was achieved in heptane:buffer medium (70:30), whereas with the lactose, the highest bioconversion yield (3.94%) was obtained in the buffer reaction system. The structures of most abundant galactosylated serine products were characterized by MS/MS. The molecular docking simulation revealed that the binding of serine/threonine derivatives to the enzyme’s active site was stronger (−4.6~−7.9 kcal/mol) than that of the natural acceptor, glucose, and mainly occurred through interactions with aromatic residues. For N-tert-butoxycarbonyl serine methyl ester (6.8%) and N-carboxybenzyl serine benzyl ester (3.4%), their binding affinities and the distances between their hydroxyl side chain and the 1′-OH group of galactose moiety were in good accordance with the quantified bioconversion yields. Despite its lower predicted bioconversion yield, the high experimental bioconversion yield obtained with N-carboxybenzyl serine methyl ester (23.2%) demonstrated the importance of the thermodynamically-driven nature of the transgalactosylation reaction.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.