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Matthew I. Gibson - One of the best experts on this subject based on the ideXlab platform.
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Site-specific conjugation of Antifreeze Proteins onto polymer-stabilized nanoparticles
Polymer Chemistry, 2019Co-Authors: Laura E. Wilkins, Alice Fayter, Caroline I. Biggs, Marc Walker, Muhammad Hasan, Matthew I. GibsonAbstract:Antifreeze Proteins (AFPs) have many potential applications, ranging from cryobiology to aerospace, if they can be incorporated into materials. Here, a range of engineered AFP mutants were prepared and site-specifically conjugated onto RAFT polymer-stabilized gold nanoparticles to generate new hybrid multivalent ice growth inhibitors. Only the SNAP-tagged AFPs lead to potent ‘Antifreeze’ active nanomaterials with His-Tag capture resulting in no activity, showing the mode of conjugation is essential. This versatile strategy will enable the development of multivalent AFPs for translational and fundamental studies.
Marilyn Griffith - One of the best experts on this subject based on the ideXlab platform.
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Antifreeze Proteins in overwintering plants: a tale of two activities
Trends in plant science, 2004Co-Authors: Marilyn Griffith, Mahmoud W. YaishAbstract:Antifreeze Proteins are found in a wide range of overwintering plants where they inhibit the growth and recrystallization of ice that forms in intercellular spaces. Unlike Antifreeze Proteins found in fish and insects, plant Antifreeze Proteins have multiple, hydrophilic ice-binding domains. Surprisingly, Antifreeze Proteins from plants are homologous to pathogenesis-related Proteins and also provide protection against psychrophilic pathogens. In winter rye ( Secale cereale ), Antifreeze Proteins accumulate in response to cold, short daylength, dehydration and ethylene, but not pathogens. Transferring single genes encoding Antifreeze Proteins to freezing-sensitive plants lowered their freezing temperatures by ∼1°C. Genes encoding dual-function plant Antifreeze Proteins are excellent models for use in evolutionary studies to determine how genes acquire new expression patterns and how Proteins acquire new activities.
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chitinase genes responsive to cold encode Antifreeze Proteins in winter cereals
Plant Physiology, 2000Co-Authors: Sansun Yeh, Daniel S C Yang, Marilyn Griffith, Barbara A Moffatt, Fei Xiong, Steven B Wiseman, Fathey Sarhan, Jean Danyluk, Yi Qi Xue, Choy L. HewAbstract:Antifreeze Proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-Antifreeze Proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.
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Antifreeze Proteins in winter rye
Physiologia Plantarum, 1997Co-Authors: Marilyn Griffith, Mervi Antikainen, Wai-ching Hon, Kaarina Pihakaski-maunsbach, Jong Un Chun, Daniel S C YangAbstract:Six Antifreeze Proteins, which have the unique ability to adsorb onto the surface of ice and inhibit its growth, have been isolated from the apoplast of winter rye leaves where ice forms at subzero temperatures. The rye Antifreeze Proteins accumulate during cold acclimation and are similar to plant pathogenesis-related Proteins, including two endoglucanase-like, two chitinase-like and two thaumatin-like Proteins. Immunolocalization of the glucanase-like Antifreeze Proteins showed that they accumulate in mesophyll cell walls facing intercellular spaces, in pectinaceous regions between adjoining mestome sheath cells, in the secondary cell walls of xylem vessels and in epidermal cell walls. Because the rye Antifreeze Proteins are located in areas where they could be in contact with ice, they may function as a barrier to the propagation of ice or to inhibit the recrystallization of ice. Antifreeze Proteins similar to pathogenesis-related Proteins were also found to accumulate in closely-related plants within the Triticum group but not in freezing-tolerant dicotyledonous plants. In winter wheat, the accumulation of Antifreeze Proteins and the development of freezing tolerance are regulated by chromosome 5. Rye Antifreeze Proteins may have evolved from pathogenesis-related Proteins, but they retain their catalytic activities and may play a dual role in increasing both freezing and disease resistance in overwintering plants.
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Antifreeze Proteins in winter rye are similar to pathogenesis related Proteins
Plant Physiology, 1995Co-Authors: Waichain Hon, Marilyn Griffith, A Mlynarz, Y C Kwok, Daniel S C YangAbstract:The ability to control extracellular ice formation during freezing is critical to the survival of freezing-tolerant plants. Antifreeze Proteins, which are Proteins that have the ability to retard ice crystal growth, were recently identified as the most abundant apoplastic Proteins in cold-acclimated winter rye (Secale cereale L.) leaves. In the experiments reported here, amino-terminal sequence comparisons, immuno-cross-reactions, and enzyme activity assays all indicated that these Antifreeze Proteins are similar to members of three classes of pathogenesis-related Proteins, namely, endochitinases, endo-beta-1,3-glucanases, and thaumatin-like Proteins. Apoplastic endochitinases and endo-beta-1,3-glucanases that were induced by pathogens in freezing-sensitive tobacco did not exhibit Antifreeze activity. Our findings suggest that subtle structural differences may have evolved in the pathogenesis-related Proteins that accumulate at cold temperatures in winter rye to confer upon these Proteins the ability to bind to ice.
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Antifreeze Proteins and their potential use in frozen foods
Biotechnology Advances, 1995Co-Authors: Marilyn Griffith, Vanya K EwartAbstract:Antifreeze Proteins (AFPs) are Proteins that have the ability to modify the growth of ice, resulting in the stabilization of ice crystals over a defined temperature range and in the inhibition of the recrystallization of ice. AFPs are found in a wide range of organisms, including bacteria, fungi, plants, invertebrates and fish. Moreover, multiple forms of AFPs are synthesized within each organism. As a result, it should be possible to select an AFP with appropriate characteristics and a suitable level of activity for a particular food product. Antifreeze Proteins may improve the quality of foods that are eaten while frozen by inhibiting recrystallization and maintaining a smooth texture. In foods that are frozen only for preservation, AFPs may inhibit recrystallization during freezing, storage, transport and thawing, thus preserving food texture by reducing cellular damage and also minimizing the loss of nutrients by reducing drip. Antifreeze Proteins are naturally present in many foods consumed as part of the human diet. However, AFPs may be introduced into other food products either by physical processes, such as mixing and soaking, or by gene transfer.
Daniel S C Yang - One of the best experts on this subject based on the ideXlab platform.
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chitinase genes responsive to cold encode Antifreeze Proteins in winter cereals
Plant Physiology, 2000Co-Authors: Sansun Yeh, Daniel S C Yang, Marilyn Griffith, Barbara A Moffatt, Fei Xiong, Steven B Wiseman, Fathey Sarhan, Jean Danyluk, Yi Qi Xue, Choy L. HewAbstract:Antifreeze Proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-Antifreeze Proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.
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Antifreeze Proteins in winter rye
Physiologia Plantarum, 1997Co-Authors: Marilyn Griffith, Mervi Antikainen, Wai-ching Hon, Kaarina Pihakaski-maunsbach, Jong Un Chun, Daniel S C YangAbstract:Six Antifreeze Proteins, which have the unique ability to adsorb onto the surface of ice and inhibit its growth, have been isolated from the apoplast of winter rye leaves where ice forms at subzero temperatures. The rye Antifreeze Proteins accumulate during cold acclimation and are similar to plant pathogenesis-related Proteins, including two endoglucanase-like, two chitinase-like and two thaumatin-like Proteins. Immunolocalization of the glucanase-like Antifreeze Proteins showed that they accumulate in mesophyll cell walls facing intercellular spaces, in pectinaceous regions between adjoining mestome sheath cells, in the secondary cell walls of xylem vessels and in epidermal cell walls. Because the rye Antifreeze Proteins are located in areas where they could be in contact with ice, they may function as a barrier to the propagation of ice or to inhibit the recrystallization of ice. Antifreeze Proteins similar to pathogenesis-related Proteins were also found to accumulate in closely-related plants within the Triticum group but not in freezing-tolerant dicotyledonous plants. In winter wheat, the accumulation of Antifreeze Proteins and the development of freezing tolerance are regulated by chromosome 5. Rye Antifreeze Proteins may have evolved from pathogenesis-related Proteins, but they retain their catalytic activities and may play a dual role in increasing both freezing and disease resistance in overwintering plants.
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Antifreeze Proteins in winter rye are similar to pathogenesis related Proteins
Plant Physiology, 1995Co-Authors: Waichain Hon, Marilyn Griffith, A Mlynarz, Y C Kwok, Daniel S C YangAbstract:The ability to control extracellular ice formation during freezing is critical to the survival of freezing-tolerant plants. Antifreeze Proteins, which are Proteins that have the ability to retard ice crystal growth, were recently identified as the most abundant apoplastic Proteins in cold-acclimated winter rye (Secale cereale L.) leaves. In the experiments reported here, amino-terminal sequence comparisons, immuno-cross-reactions, and enzyme activity assays all indicated that these Antifreeze Proteins are similar to members of three classes of pathogenesis-related Proteins, namely, endochitinases, endo-beta-1,3-glucanases, and thaumatin-like Proteins. Apoplastic endochitinases and endo-beta-1,3-glucanases that were induced by pathogens in freezing-sensitive tobacco did not exhibit Antifreeze activity. Our findings suggest that subtle structural differences may have evolved in the pathogenesis-related Proteins that accumulate at cold temperatures in winter rye to confer upon these Proteins the ability to bind to ice.
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extraction and isolation of Antifreeze Proteins from winter rye secale cereale l leaves
Plant Physiology, 1994Co-Authors: Wai-ching Hon, Marilyn Griffith, Pele Chong, Daniel S C YangAbstract:Apoplastic extracts of cold-acclimated winter rye (Secale cereale L. cv Musketeer) leaves were previously shown to exhibit Antifreeze activity. The objectives of the present study were to identify and characterize individual Antifreeze Proteins present in the apoplastic extracts. The highest protein concentrations and Antifreeze activity were obtained when the leaf apoplast was extracted with ascorbic acid and either CaCl2 or MgSO4. Seven major polypeptides were purified from these extracts by one-dimensional sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis under nonreducing conditions. The five larger polypeptides, of 19, 26, 32, 34, and 36 kD, exhibited significant levels of Antifreeze activity, whereas the 11- and 13-kD polypeptides showed only weak activity. Five of these polypeptides migrated with higher apparent molecular masses on SDS gels after treatment with 0.1 M dithiothreitol, which indicated the presence of intramolecular disulfide bonds. The apparent reduction of the disulfide bonds did not eliminate Antifreeze activity in four of the polypeptides that contained intramolecular disulfide bonds and exhibited significant levels of Antifreeze activity. The amino acid compositions of these polypeptides were similar in that they were all relatively enriched in the residues Asp/Asn, Glu/Gln, Ser, Thr, Gly, and Ala; they all lacked His, except for the 26-kD polypeptide, and they contained up to 5% Cys residues. These polypeptides were examined with antisera to other cystine-containing Antifreeze Proteins from fish and insects, and no common epitopes were detected. We conclude that cold-acclimated winter rye leaves produce multiple polypeptides with Antifreeze activity that appear to be distinct from Antifreezes produced by fish and insects.
Peter L Davies - One of the best experts on this subject based on the ideXlab platform.
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Experimental correlation between thermal hysteresis activity and the distance between Antifreeze Proteins on an ice surface
RSC Advances, 2015Co-Authors: Ran Drori, Peter L Davies, Ido BraslavskyAbstract:Temperature-controlled microfluidic devices and fluorescence microscopy illustrate the correlation between freezing-point depression and the distance between Antifreeze Proteins on an ice surface.
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anchored clathrate waters bind Antifreeze Proteins to ice
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Christopher P Garnham, Robert L Campbell, Peter L DaviesAbstract:The mechanism by which Antifreeze Proteins (AFPs) irreversibly bind to ice has not yet been resolved. The ice-binding site of an AFP is relatively hydrophobic, but also contains many potential hydrogen bond donors/acceptors. The extent to which hydrogen bonding and the hydrophobic effect contribute to ice binding has been debated for over 30 years. Here we have elucidated the ice-binding mechanism through solving the first crystal structure of an Antarctic bacterial AFP. This 34-kDa domain, the largest AFP structure determined to date, folds as a Ca2+-bound parallel beta-helix with an extensive array of ice-like surface waters that are anchored via hydrogen bonds directly to the polypeptide backbone and adjacent side chains. These bound waters make an excellent three-dimensional match to both the primary prism and basal planes of ice and in effect provide an extensive X-ray crystallographic picture of the AFP∶ice interaction. This unobstructed view, free from crystal-packing artefacts, shows the contributions of both the hydrophobic effect and hydrogen bonding during AFP adsorption to ice. We term this mode of binding the “anchored clathrate” mechanism of AFP action.
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the basis for hyperactivity of Antifreeze Proteins
Cryobiology, 2006Co-Authors: Andrew J Scotter, Laurie A Graham, Christopher B Marshall, Jack A Gilbert, Christopher P Garnham, Peter L DaviesAbstract:Antifreeze Proteins (AFPs) bind to the surface of ice crystals and lower the non-equilibrium freezing temperature of the icy solution below its melting point. We have recently reported the discovery of three novel hyperactive AFPs from a bacterium, a primitive insect and a fish, which, like two hyperactive AFPs previously recognized in beetles and moths, are considerably better at depressing the freezing point than most fish AFPs. When cooled below the non-equilibrium freezing temperature, ice crystals formed in the presence of any of five distinct, moderately active fish AFPs grow suddenly along the c-axis. Ice crystals formed in the presence of any of the five evolutionarily and structurally distinct hyperactive AFPs remain stable to lower temperatures, and then grow explosively in a direction normal to the c-axis when cooled below the freezing temperature. We argue that this one consistent distinction in the behaviour of these two classes of AFPs is the key to hyperactivity. Whereas both AFP classes bind irreversibly to ice, the hyperactive AFPs are better at preventing ice growth out of the basal planes.
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glycine rich Antifreeze Proteins from snow fleas
Science, 2005Co-Authors: Laurie A Graham, Peter L DaviesAbstract:We purified Antifreeze Proteins from winter-active snow fleas, Hypogastrura harveyi. These 6.5- and 15.7-kilodalton thermolabile Proteins are glycine-rich (45% of the residues), and the short isoform is composed of the tripeptide repeat Gly-X-X. This makes them very different from other Antifreeze Proteins, including two from insects, suggesting independent adaptation to freezing environments.
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Purification of Antifreeze Proteins by adsorption to ice
Biochemical and biophysical research communications, 2003Co-Authors: Michael J. Kuiper, Virginia K Walker, Christopher Lankin, Sherry Y. Gauthier, Peter L DaviesAbstract:Antifreeze Proteins (AFPs) can protect organisms from freezing injury by adsorbing to ice and inhibiting its growth. We describe here a method where ice, grown on a cold finger, is used to selectively adsorb and purify these ice-binding Proteins from a crude mixture. Type III recombinant AFP was enriched approximately 50-fold after one round of partitioning into ice and purified to homogeneity by a second round. This method can also be used to purify non-ice-binding Proteins by linkage to AFP domains as demonstrated by the recovery of a 50 kDa maltose-binding protein-AFP fusion from a crude lysate of Escherichia coli.
Laura E. Wilkins - One of the best experts on this subject based on the ideXlab platform.
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Site-specific conjugation of Antifreeze Proteins onto polymer-stabilized nanoparticles
Polymer Chemistry, 2019Co-Authors: Laura E. Wilkins, Alice Fayter, Caroline I. Biggs, Marc Walker, Muhammad Hasan, Matthew I. GibsonAbstract:Antifreeze Proteins (AFPs) have many potential applications, ranging from cryobiology to aerospace, if they can be incorporated into materials. Here, a range of engineered AFP mutants were prepared and site-specifically conjugated onto RAFT polymer-stabilized gold nanoparticles to generate new hybrid multivalent ice growth inhibitors. Only the SNAP-tagged AFPs lead to potent ‘Antifreeze’ active nanomaterials with His-Tag capture resulting in no activity, showing the mode of conjugation is essential. This versatile strategy will enable the development of multivalent AFPs for translational and fundamental studies.