Skip to main content

Advertisement

Log in

Characterization of Leuconostoc mesenteroides NRRL B-512F dextransucrase (DSRS) and identification of amino-acid residues playing a key role in enzyme activity

  • ORIGINAL PAPER
  • Published:
Applied Microbiology and Biotechnology Aims and scope Submit manuscript

Abstract

Dextransucrase (DSRS) from Leuconostoc mesenteroides NRRL B-512F is a glucosyltransferase that catalyzes the synthesis of soluble dextran from sucrose or oligosaccharides when acceptor molecules, like maltose, are present. The L. mesenteroides NRRL B-512F dextransucrase-encoding gene (dsrS) was amplified by the polymerase chain reaction and cloned in an overexpression plasmid. The characteristics of DSRS were found to be similar to the characteristics of the extracellular dextransucrase produced by L. mesenteroides NRRL B-512F. The enzyme also exhibited a high homology with other glucosyltransferases. In order to identify critical amino acid residues, the DSRS sequence was aligned with glucosyltransferase sequences and four amino acid residues were selected for site- directed mutagenesis experiments: aspartic acid 511, aspartic acid 513, aspartic acid 551 and histidine 661. Asp-511, Asp-513 and Asp-551 were independently replaced with asparagine and His-661 with arginine. Mutation at Asp-511 and Asp-551 completely suppressed dextran and oligosaccharide synthesis activities, showing that at least two carboxyl groups (Asp-511 and Asp-551) are essential for the catalysis process. However, glucan-binding properties were retained, showing that DSRS has a two-domain structure like other glucosyltransferases. Mutations at Asp-513 and His-661 resulted in greatly reduced dextransucrase activity. According to amino acid sequence alignments of glucosyltransferases, α-amylases or cyclodextrin glucanotransferases, His-661 may have a hydrogen-bonding function.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Author information

Authors and Affiliations

Authors

Additional information

Received: 16 April 1997 / Received revision: 17 June 1997 / Accepted: 23 June 1997

Rights and permissions

Reprints and permissions

About this article

Cite this article

Monchois, V., Remaud-Simeon, M., Russell, R. et al. Characterization of Leuconostoc mesenteroides NRRL B-512F dextransucrase (DSRS) and identification of amino-acid residues playing a key role in enzyme activity. Appl Microbiol Biotechnol 48, 465–472 (1997). https://doi.org/10.1007/s002530051081

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/s002530051081

Keywords

Navigation