Characterization of AlgMsp, an alginate lyase from Microbulbifer sp. 6532A

PLoS One. 2014 Nov 19;9(11):e112939. doi: 10.1371/journal.pone.0112939. eCollection 2014.

Abstract

Alginate is a polysaccharide produced by certain seaweeds and bacteria that consists of mannuronic acid and guluronic acid residues. Seaweed alginate is used in food and industrial chemical processes, while the biosynthesis of bacterial alginate is associated with pathogenic Pseudomonas aeruginosa. Alginate lyases cleave this polysaccharide into short oligo-uronates and thus have the potential to be utilized for both industrial and medicinal applications. An alginate lyase gene, algMsp, from Microbulbifer sp. 6532A, was synthesized as an E.coli codon-optimized clone. The resulting 37 kDa recombinant protein, AlgMsp, was expressed, purified and characterized. The alginate lyase displayed highest activity at pH 8 and 0.2 M NaCl. Activity of the alginate lyase was greatest at 50°C; however the enzyme was not stable over time when incubated at 50°C. The alginate lyase was still highly active at 25°C and displayed little or no loss of activity after 24 hours at 25°C. The activity of AlgMsp was not dependent on the presence of divalent cations. Comparing activity of the lyase against polymannuronic acid and polyguluronic acid substrates showed a higher turnover rate for polymannuronic acid. However, AlgMSP exhibited greater catalytic efficiency with the polyguluronic acid substrate. Prolonged AlgMsp-mediated degradation of alginate produced dimer, trimer, tetramer, and pentamer oligo-uronates.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alteromonadaceae / enzymology*
  • Alteromonadaceae / genetics
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Circular Dichroism
  • Enzyme Stability
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Hexuronic Acids / metabolism
  • Polysaccharide-Lyases / chemistry*
  • Polysaccharide-Lyases / genetics
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / genetics
  • Substrate Specificity

Substances

  • Bacterial Proteins
  • Hexuronic Acids
  • Recombinant Proteins
  • guluronic acid
  • mannuronic acid
  • Polysaccharide-Lyases
  • poly(beta-D-mannuronate) lyase

Grant support

This work was supported by grants from the United States Department of Defense (DM102823) to DCN. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.