Evolving strategies for marine enzyme engineering: recent advances on the molecular modification of alginate lyase

Abstract

Alginate, an acidic polysaccharide, is formed by β-d-mannuronate (M) and α-l-guluronate (G). As a type of polysaccharide lyase, alginate lyase can efficiently degrade alginate into alginate oligosaccharides, having potential applications in the food, medicine, and agriculture fields. However, the application of alginate lyase has been limited due to its low catalytic efficiency and poor temperature stability. In recent years, various structural features of alginate lyase have been determined, resulting in modification strategies that can increase the applicability of alginate lyase, making it important to summarize and discuss the current evidence. In this review, we summarized the structural features and catalytic mechanisms of alginate lyase. Molecular modification strategies, such as rational design, directed evolution, conserved domain recombination, and non-catalytic domain truncation, are also described in detail. Lastly, the application of alginate lyase is discussed. This comprehensive summary can inform future applications of alginate lyases.

Keywords: Alginate lyase; Application; Catalytic mechanism; Molecular modification; Structure.

Fig. 1

Three-dimensional structures of alginate lyases from different families. (The structure information of alginate lyase in the figure comes from the website: http://www.cazy.org; https://www.rcsb.org). PL5 family: A1-II (PDB:1QAZ); PL6 family: AlyGC (PDB: 5GKD), BcelPL6 (PDB: 5Z9T); PL7 family: FlAlyA (PDB: 5Y33); PL14 family: VaL-1 (PDB: 3A0N); PL15 family: Atu3025(PDB:3A0O); PL17 family: Al g17c (PDB: 4OK2) PL18 family: Aly-SJ02 (PDB:4Q8K); PL31 family: PsAly (PDB: 6KFN); PL36 family: Aly36B (PDB: 6KCW); PL39 family: DP0100 (PDB:6JP4)

Fig. 2

Schematic diagram of the catalytic mechanism of alginate lyase. A syn-elimination; B anti-elimination