Enzymatic Synthesis of Rhamnose Containing Chemicals by Reverse Hydrolysis

PLoS One. 2015 Oct 27;10(10):e0140531. doi: 10.1371/journal.pone.0140531. eCollection 2015.

Abstract

Rhamnose containing chemicals (RCCs) are widely occurred in plants and bacteria and are known to possess important bioactivities. However, few of them were available using the enzymatic synthesis method because of the scarcity of the α-L-rhamnosidases with wide acceptor specificity. In this work, an α-L-rhamnosidase from Alternaria sp. L1 was expressed in Pichia pastroris strain GS115. The recombinant enzyme was purified and used to synthesize novel RCCs through reverse hydrolysis in the presence of rhamnose as donor and mannitol, fructose or esculin as acceptors. The effects of initial substrate concentrations, reaction time, and temperature on RCC yields were investigated in detail when using mannitol as the acceptor. The mannitol derivative achieved a maximal yield of 36.1% by incubation of the enzyme with 0.4 M L-rhamnose and 0.2 M mannitol in pH 6.5 buffers at 55°C for 48 h. In identical conditions except for the initial acceptor concentrations, the maximal yields of fructose and esculin derivatives reached 11.9% and 17.9% respectively. The structures of the three derivatives were identified to be α-L-rhamnopyranosyl-(1→6')-D-mannitol, α-L-rhamnopyranosyl-(1→1')-β-D-fructopyranose, and 6,7-dihydroxycoumarin α-L-rhamnopyranosyl-(1→6')-β-D-glucopyranoside by ESI-MS and NMR spectroscopy. The high glycosylation efficiency as well as the broad acceptor specificity of this enzyme makes it a powerful tool for the synthesis of novel rhamnosyl glycosides.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternaria / enzymology*
  • Glycoside Hydrolases / chemistry
  • Glycoside Hydrolases / genetics*
  • Glycosides / chemistry
  • Glycosylation
  • Hydrolysis
  • Nuclear Magnetic Resonance, Biomolecular
  • Pichia / genetics*
  • Rhamnose / biosynthesis*
  • Rhamnose / chemistry
  • Rhamnose / genetics
  • Substrate Specificity

Substances

  • Glycosides
  • Glycoside Hydrolases
  • alpha-L-rhamnosidase
  • Rhamnose

Grants and funding

This work was supported in parts by the Major State Basic Research Development Program of China (973 Program) (No. 2012CB822102), National Major Scientific and Technological Special Project for Significant New Drugs Development (2012ZX09502001-005), National High Technology Research and Development Program of China (863 Program) (No. 2012AA021504), Science and Technology Development Project of Shandong Province (2014GSF121006, 2015GSF121004), and the Keygrant Project of Chinese Ministry of Education (No.313033). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.