Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus
A molecular and crystallographic characterization of antifreeze proteins from the sea ice diatom Fragilariopsis cylindrus (fcAFPs) is presented here. The molecular study relies on sequence analyses, phylogenetic studies, gene and protein expression analyses. These AFPs constitute a multigene family...
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Universität Bremen
2011
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Online Access: | https://media.suub.uni-bremen.de/handle/elib/224 https://nbn-resolving.org/urn:nbn:de:gbv:46-00102347-18 |
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ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/224 2023-05-15T18:17:22+02:00 Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus Gefrierschutzproteine aus der Meereisdiatomee Fragilariopsis cylindrus Bayer, Maddalena Bathmann, Ulrich Dieckmann, Gerhard Cembella, Allan 2011-11-14 application/pdf https://media.suub.uni-bremen.de/handle/elib/224 https://nbn-resolving.org/urn:nbn:de:gbv:46-00102347-18 eng eng Universität Bremen FB2 Biologie/Chemie https://media.suub.uni-bremen.de/handle/elib/224 urn:nbn:de:gbv:46-00102347-18 info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) CC-BY Sea Ice Biology Diatoms Antifreeze Protein AFP Fragilariopsis cylindrus 570 570 Life sciences ddc:570 Dissertation doctoralThesis 2011 ftsubbremen 2022-11-09T07:09:20Z A molecular and crystallographic characterization of antifreeze proteins from the sea ice diatom Fragilariopsis cylindrus (fcAFPs) is presented here. The molecular study relies on sequence analyses, phylogenetic studies, gene and protein expression analyses. These AFPs constitute a multigene family of isoforms with a conserved antifreeze domain. The exposure of F. cylindrus to subzero conditions typical for sea ice brine caused differential regulation of the isoforms, as revealed by gene expression analysis. Some fcAFP genes were downregulated to nearly zero, whereas selected isoforms were strongly upregulated (up to 200-fold). Differential gene regulation was reflected in protein expression pattern. The widespread occurrence of fcAFPs and fcAFP-like proteins in polar or cold-tolerant organisms further underlines their importance as elements of adaptation to subzero conditions. Several events of horizontal gene transfer seem to have contributed to the distribution of the fcAFP genes. These results suggest a strong relevance of these proteins for F. cylindrus, probably contributing to its dominat position within sea ice assemblages. Studies with a recombinant isoform of fcAFP, chosen based on the molecular results, confirmed its antifreeze activity. The protein caused moderate freezing point depression and strong recrystallization inhibition. These effects were enhanced in concentrated saline solutions. In order to shed light on the physical antifreeze mechanism of this protein, its interaction with ice is presented in more detail here. Several crystal planes are suggested for preferential protein-ice interaction. Habit modification in the presence of fcAFPs, with inhibited ice growth on the lateral (prismatic) planes, indicates binding on the primary and secondary prismatic faces. Pitting observed on the basal plane of a pure crystal submerged in an fcAFP solution suggests further protein binding on non-lateral planes of the ice crystal. The most prominent feature shown here is the influence of fcAFPs on ice ... Doctoral or Postdoctoral Thesis Sea ice Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
Sea Ice Biology Diatoms Antifreeze Protein AFP Fragilariopsis cylindrus 570 570 Life sciences ddc:570 |
spellingShingle |
Sea Ice Biology Diatoms Antifreeze Protein AFP Fragilariopsis cylindrus 570 570 Life sciences ddc:570 Bayer, Maddalena Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus |
topic_facet |
Sea Ice Biology Diatoms Antifreeze Protein AFP Fragilariopsis cylindrus 570 570 Life sciences ddc:570 |
description |
A molecular and crystallographic characterization of antifreeze proteins from the sea ice diatom Fragilariopsis cylindrus (fcAFPs) is presented here. The molecular study relies on sequence analyses, phylogenetic studies, gene and protein expression analyses. These AFPs constitute a multigene family of isoforms with a conserved antifreeze domain. The exposure of F. cylindrus to subzero conditions typical for sea ice brine caused differential regulation of the isoforms, as revealed by gene expression analysis. Some fcAFP genes were downregulated to nearly zero, whereas selected isoforms were strongly upregulated (up to 200-fold). Differential gene regulation was reflected in protein expression pattern. The widespread occurrence of fcAFPs and fcAFP-like proteins in polar or cold-tolerant organisms further underlines their importance as elements of adaptation to subzero conditions. Several events of horizontal gene transfer seem to have contributed to the distribution of the fcAFP genes. These results suggest a strong relevance of these proteins for F. cylindrus, probably contributing to its dominat position within sea ice assemblages. Studies with a recombinant isoform of fcAFP, chosen based on the molecular results, confirmed its antifreeze activity. The protein caused moderate freezing point depression and strong recrystallization inhibition. These effects were enhanced in concentrated saline solutions. In order to shed light on the physical antifreeze mechanism of this protein, its interaction with ice is presented in more detail here. Several crystal planes are suggested for preferential protein-ice interaction. Habit modification in the presence of fcAFPs, with inhibited ice growth on the lateral (prismatic) planes, indicates binding on the primary and secondary prismatic faces. Pitting observed on the basal plane of a pure crystal submerged in an fcAFP solution suggests further protein binding on non-lateral planes of the ice crystal. The most prominent feature shown here is the influence of fcAFPs on ice ... |
author2 |
Bathmann, Ulrich Dieckmann, Gerhard Cembella, Allan |
format |
Doctoral or Postdoctoral Thesis |
author |
Bayer, Maddalena |
author_facet |
Bayer, Maddalena |
author_sort |
Bayer, Maddalena |
title |
Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus |
title_short |
Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus |
title_full |
Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus |
title_fullStr |
Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus |
title_full_unstemmed |
Antifreeze Proteins from the Sea Ice Diatom Fragilariopsis cylindrus |
title_sort |
antifreeze proteins from the sea ice diatom fragilariopsis cylindrus |
publisher |
Universität Bremen |
publishDate |
2011 |
url |
https://media.suub.uni-bremen.de/handle/elib/224 https://nbn-resolving.org/urn:nbn:de:gbv:46-00102347-18 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/224 urn:nbn:de:gbv:46-00102347-18 |
op_rights |
info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) |
op_rightsnorm |
CC-BY |
_version_ |
1766191559544406016 |