Biochemical and Structural Characterization of the Complex Agarolytic Enzyme System from the Marine Bacterium Zobellia galactanivorans

Abstract

Background: Bacterial agarolytic systems are frequent and play an important role in algal biomass conversion. Results: Structural and biochemical analyses of several agar-related enzymes reveal details on substrate recognition and complementary roles. Conclusion:The diversity of agar-related enzymes within a bacterial organism reflects the complexity of the natural substrate. Significance: Marine microbes employ complex systems to catalyze degradation of polysaccharides with unique structural characteristics.

Structure-Function Analysis of a Broad Specificity Populus trichocarpa Endo-β-glucanase Reveals an Evolutionary Link between Bacterial Licheninases and Plant XTH Gene Products

“…Although enzyme structure-function analyses continue to shed light on protein loop differences that fine-tune specificity for particular linear galactans and glucans among bacterial members (15,79,80), the evolutionary steps leading to the dramatic structural features of plant XTH gene products have remained essentially unknown.…”

Substrate Recognition and Hydrolysis by a Family 50 exo-β-Agarase, Aga50D, from the Marine Bacterium Saccharophagus degradans

“…3). This binding pattern suggests a preference for the product binding the ϩ1 and ϩ2 subsites, which is in contrast to the GH16 ␤-agarases, where products appear to bind with preference to the minus (Ϫ) subsites (7,11).…”

“…In accordance with their role of generating longer oligosaccharides, the crystal structures of GH16 endo-␤-agarases (AgaA, AgaB, and AgaD) from Zobellia galactanivorans and the GH86 endo-␤-porphyranase from Bacteroides plebeius, revealed open and extended substrate binding clefts (11,21,25,26). In contrast, the structures of GH117 exo-␣-neoagarobiose hydrolases, from S. degradans (27), Z. galactanivorans (28), and B. plebeius (17), displayed small substrate binding pockets sufficient to bind and cleave a disaccharide.…”

Marine enzymes and food industry: insight on existing and potential interactions

“…In the overall this recombinant enzyme was considered promising for application in a cost effective industrial application. Cloning and expression of genes encoding putative agarases from the marine bacterium Zobellia galactanivorans into E. coli BL21 was also the strategy used to gain insight on the enzymatic complex accountable for agarose hydrolysis (Hehemann et al, 2012). Accordingly, the authors were able to establish a scenario for the concerted action of three agarases, each with a specific role: one of these, a highly specific β-agarase, AgaD, would be responsible for the production of long oligosaccharide chains for the action of the remaining agarases.…”