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A novel ulvan lyase family with broad-spectrum activity from the ulvan utilisation loci of Formosa agariphila KMM 3901.

ABSTRACT: Ulvan, which is one of the major structural polysaccharides of the cell walls of green macroalgae, is degraded by ulvan lyases via the ?-elimination mechanism with the release of oligosaccharides that have unsaturated 4-deoxy-L-threo-hex-4-enopyranosiduronic acid (?) at the non-reducing end. These ulvan lyases belong to the PL24 or PL25 or PL28 family in the CAZy database. In this study, we identify and biochemically characterise a periplasmic novel broad-spectrum ulvan lyase from Formosa agariphila KMM 3901. The lyase was overexpressed in Escherichia coli, and the purified recombinant enzyme depolymerised ulvan in an endolytic manner with a Km of 0.77?mg/ml, and displayed optimum activity at 40?°C and pH 8. This lyase also degraded heparan sulphate and chondroitin sulphate. Detailed analyses of the end-products of the enzymatic degradation of ulvan using 1H- and 13C-NMR and LC-MS revealed an unsaturated disaccharide (?Rha3S) and a tetrasaccharide (?Rha3S-Xyl-Rha) as the principal end-products. In contrast to the previously described ulvan lyases, this novel lyase is mostly composed of ?-helices that form an (?/?)6 incomplete toroid domain and displays a remarkably broad-spectrum activity. This novel lyase is the first member of a new family of ulvan lyases.

SUBMITTER: Konasani VR

PROVIDER: S-EPMC6168547 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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A novel ulvan lyase family with broad-spectrum activity from the ulvan utilisation loci of Formosa agariphila KMM 3901.

Konasani Venkat Rao VR Jin Chunsheng C Karlsson Niclas G NG Albers Eva E

Scientific reports 20181002 1

Ulvan, which is one of the major structural polysaccharides of the cell walls of green macroalgae, is degraded by ulvan lyases via the β-elimination mechanism with the release of oligosaccharides that have unsaturated 4-deoxy-L-threo-hex-4-enopyranosiduronic acid (∆) at the non-reducing end. These ulvan lyases belong to the PL24 or PL25 or PL28 family in the CAZy database. In this study, we identify and biochemically characterise a periplasmic novel broad-spectrum ulvan lyase from Formosa agarip ...[more]

PMID: 30279430

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Project description:Ulvan is an important marine polysaccharide. Bacterial ulvan lyases play important roles in ulvan degradation and marine carbon cycling. Until now, only a small number of ulvan lyases have been characterized. Here, a new ulvan lyase, Uly1, belonging to polysaccharide lyase family 24 (PL24) from the marine bacterium Catenovulum maritimum, is characterized. The optimal temperature and pH for Uly1 to degrade ulvan are 40°C and pH 9.0, respectively. Uly1 degrades ulvan polysaccharides in the endolytic manner, mainly producing ΔRha3S, consisting of an unsaturated 4-deoxy-l-threo-hex-4-enopyranosiduronic acid and a 3-O-sulfated α-l-rhamnose. The structure of Uly1 was resolved at a 2.10-Å resolution. Uly1 adopts a seven-bladed β-propeller architecture. Structural and site-directed mutagenesis analyses indicate that four highly conserved residues, H128, H149, Y223, and R239, are essential for catalysis. H128 functions as both the catalytic acid and base, H149 and R239 function as the neutralizers, and Y223 plays a supporting role in catalysis. Structural comparison and sequence alignment suggest that Uly1 and many other PL24 enzymes may directly bind the substrate near the catalytic residues for catalysis, different from the PL24 ulvan lyase LOR_107, which adopts a two-stage substrate binding process. This study provides new insights into ulvan lyases and ulvan degradation. IMPORTANCE Ulvan is a major cell wall component of green algae of the genus Ulva. Many marine heterotrophic bacteria can produce extracellular ulvan lyases to degrade ulvan for a carbon nutrient. In addition, ulvan has a range of physiological bioactivities based on its specific chemical structure. Ulvan lyase thus plays an important role in marine carbon cycling and has great potential in biotechnological applications. However, only a small number of ulvan lyases have been characterized over the past 10 years. Here, based on biochemical and structural analyses, a new ulvan lyase of polysaccharide lyase family 24 is characterized, and its substrate recognition and catalytic mechanisms are revealed. Moreover, a new substrate binding process adopted by PL24 ulvan lyases is proposed. This study offers a better understanding of bacterial ulvan lyases and is helpful for studying the application potentials of ulvan lyases.

Dataset Information

A novel ulvan lyase family with broad-spectrum activity from the ulvan utilisation loci of Formosa agariphila KMM 3901.

Publications

A novel ulvan lyase family with broad-spectrum activity from the ulvan utilisation loci of Formosa agariphila KMM 3901.

Similar Datasets

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