Characterization of an antifreeze protein from the polar diatom Fragilariopsis cylindrus and its relevance in sea ice

Bayer‐Giraldi, Maddalena; Weikusat, Ilka; Besir, Hüseyin; Dieckmann, Gerhard

doi:10.1016/j.cryobiol.2011.08.006

Cited by 86 publications

(113 citation statements)

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“…The results showed an effect less marked with respect to that displayed by a recombinant AFP from the sea-ice diatom, which is a strong inhibitor of recrystallization compared to other AFPs. 44 However, the comparison between two very different molecules, such as a polysaccharide and a protein, may not be appropriate or rigorous. Besides ice-binding patterns, the size, composition and conformation of the molecules also play a role in modulating the effect on ice.…”

Section: Discussionmentioning

confidence: 99%

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A Unique Capsular Polysaccharide Structure from the Psychrophilic Marine Bacterium Colwellia psychrerythraea 34H That Mimics Antifreeze (Glyco)proteins

et al. 2015

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ABSTRACT:The low temperatures of polar regions and high altitude environments, especially icy habitats, present challenges for many microorganisms. Their ability to live under subfreezing conditions implies the production of compounds conferring cryotolerance. Colwellia psychrerythraea 34H, a -proteobacterium isolated from subzero Arctic marine sediments, provides a model for the study of life in cold environments. We report here the identification and detailed molecular primary and secondary structures of capsular polysaccharide from C. psychrerythraea 34H cells. The polymer was isolated in the water layer when cells were extracted by phenol/water and characterized by one-and two-dimensional NMR spectroscopy together with chemical analysis. Molecular mechanic and dynamic calculations were also performed. The polysaccharide consists of a tetrasaccharidic repeating unit containing two amino sugars and two uronic acids bearing threonine as substituent. The structural features of this unique polysaccharide resemble those present in antifreeze proteins and glycoproteins. These results suggest a possible correlation between the capsule structure and the ability of C. psychrerythraea to colonize subfreezing marine environments.

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Section: Discussionmentioning

confidence: 99%

“…The protein was provided by M. Bayer-Giraldi and produced recombinantly in E. coli as described previously. 44 As a negative control we used chondroitin, a capsular polysaccharide produced by an engineered E. coli K4. 46 All particle solutions (CPS, AFP and chondroitin) were measured at the same concentration of 6.6 μM.…”

Section: Methodsmentioning

confidence: 99%

A Unique Capsular Polysaccharide Structure from the Psychrophilic Marine Bacterium Colwellia psychrerythraea 34H That Mimics Antifreeze (Glyco)proteins

et al. 2015

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Section: S Ea Ice Covers Extensive Regions Of the Arctic And Southernmentioning

confidence: 99%

“…However, there is increasing evidence that the processes of seawater freezing can be biologically mediated by ice-binding proteins and EPS secreted by bacteria and algae. These compounds can alter ice structure (14,15,(21)(22)(23)(24)(25)(26) and, in the case of EPS, also form physico-chemical buffers between the organisms and the surrounding brines and ice matrix (9,14,17).When sea ice melts, its dissolved and particulate constituents are released into the surface waters (27, 28), contributing to the microbial dynamics in both the melting ice and melt waters (19,(29)(30)(31). Physical aggregation of EPS in seawater to form larger particles may promote the sinking of particulate organic matter from the surface waters (19, 32), or produce EPS foams that are Significance Many marine microalgae and bacteria secrete polysaccharide gels (exopolymers) in response to environmental stresses, such as the freezing temperatures and salt concentrations that organisms experience when in sea ice.…”

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Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Underwood

Aslam

Michel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Sea ice can contain high concentrations of dissolved organic carbon (DOC), much of which is carbohydrate-rich extracellular polymeric substances (EPS) produced by microalgae and bacteria inhabiting the ice. Here we report the concentrations of dissolved carbohydrates (dCHO) and dissolved EPS (dEPS) in relation to algal standing stock [estimated by chlorophyll (Chl) a concentrations] in sea ice from six locations in the Southern and Arctic Oceans. Concentrations varied substantially within and between sampling sites, reflecting local ice conditions and biological content. However, combining all data revealed robust statistical relationships between dCHO concentrations and the concentrations of different dEPS fractions, Chl a, and DOC. These relationships were true for whole ice cores, bottom ice (biomass rich) sections, and colder surface ice. The distribution of dEPS was strongly correlated to algal biomass, with the highest concentrations of both dEPS and non-EPS carbohydrates in the bottom horizons of the ice. Complex EPS was more prevalent in colder surface sea ice horizons. Predictive models (validated against independent data) were derived to enable the estimation of dCHO concentrations from data on ice thickness, salinity, and vertical position in core. When Chl a data were included a higher level of prediction was obtained. The consistent patterns reflected in these relationships provide a strong basis for including estimates of regional and seasonal carbohydrate and dEPS carbon budgets in coupled physical-biogeochemical models, across different types of sea ice from both polar regions. S ea ice covers extensive regions of the Arctic and SouthernOceans, as well as some subpolar seas, and exhibits major annual, interannual, and long-term climate-related variability in age, thickness, and structure (1-3). Sea ice is not an inert physical barrier to air-ocean exchange (4), and both microbial activity and physico-chemical reactions within the ice contribute to regional-scale biogeochemical processes at the air-ocean surface interface (5).Sea ice provides a range of habitats for diverse biological assemblages that are characterized by high standing stocks of microalgae and bacteria (6). These microorganisms produce large quantities of dissolved organic carbon (DOC), often in the form of carbohydrate-rich extracellular polymeric substances (EPS) (7). Microbial EPS exist in a dynamic equilibrium from dissolved polysaccharides (dEPS <0.2 μm) to complex particulate EPS that can form gels on the millimeter to centimeter scale (8). Here we focus on the biologically relevant dissolved carbohydrates (dCHO) that constitute a substantial fraction of the DOC in sea ice (9-13) (Fig. 1). dCHO are concentrated from sea ice DOC by dialysis (>8 kDa), with subsequent treatment allowing the definition of four subcomponents of the total dCHO pool: (i) dissolved uronic acids (dUA), produced by ice diatoms and ice bacteria (14-16), that confer strong cross-linkages between polymer chains (8), forming low solubility EPS complexes w...

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“…AY30 (8,9). 4 LeIBP shows a remarkable sequence similarity with IBPs from other fungi, diatoms, or yeast. Comparison of the amino acid sequence of LeIBP to those of other IBPs revealed that LeIBP has 56 and 58% identity to IBPs found in the snow mold Typhula ishikariensis (TisIBP) and in the polar diatom Navicula glaciei (NglIBP), respectively.…”

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confidence: 99%

Structural Basis for Antifreeze Activity of Ice-binding Protein from Arctic Yeast

Lee

Park

et al. 2012

Journal of Biological Chemistry

122

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Background: Ice-binding proteins improve the cold tolerance of cells by inhibiting ice growth and recrystallization. Results: Crystal structure and mutagenesis data of LeIBP suggests the B face as an ice-binding site. Conclusion: LeIBP structure adopts a ␤-helical fold and the aligned Thr/Ser/Ala residues are critical for ice binding. Significance: LeIBP structure can serve as a structural model for a large number of IBPs.

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Characterization of an antifreeze protein from the polar diatom Fragilariopsis cylindrus and its relevance in sea ice

Cited by 86 publications

References 69 publications

A Unique Capsular Polysaccharide Structure from the Psychrophilic Marine Bacterium Colwellia psychrerythraea 34H That Mimics Antifreeze (Glyco)proteins

A Unique Capsular Polysaccharide Structure from the Psychrophilic Marine Bacterium Colwellia psychrerythraea 34H That Mimics Antifreeze (Glyco)proteins

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Structural Basis for Antifreeze Activity of Ice-binding Protein from Arctic Yeast

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