Characterization of a Novel PolyM-Preferred Alginate Lyase from Marine Vibrio splendidus OU02.

Alginate lyases are enzymes that degrade alginate into oligosaccharides which possess a variety of biological activities. Discovering and characterizing novel alginate lyases has great significance for industrial and medical applications. In this study, we reported a novel alginate lyase, AlyA-OU02, derived from the marine Vibrio splendidus OU02. The BLASTP searches showed that AlyA-OU02 belonged to polysaccharide lyase family 7 (PL7) and contained two consecutive PL7 domains, which was rare among the alginate lyases in PL7 family. Both the two domains, AlyA ^a and AlyA ^b , had lyase activities, while AlyA ^a exhibited polyM preference, and AlyA ^b was polyG-preferred. In addition, the enzyme activity of AlyA ^a was much higher than AlyA ^b at 25 °C. The full-length enzyme of AlyA-OU02 showed polyM preference, which was the same as AlyA ^a . AlyA ^a degraded alginate into di-, tri-, and tetra-alginate oligosaccharides, while AlyA ^b degraded alginate into tri-, tetra-, and penta-alginate oligosaccharides. The degraded products of AlyA-OU02 were similar to AlyA ^a . Our work provided a potential candidate in the application of alginate oligosaccharide production and the characterization of the two domains might provide insights into the use of alginate of this organism.