An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes
Many microbes that survive in cold environments are known to secrete ice-binding proteins (IBPs). The structure–function relationship of these proteins remains unclear. A microbial IBP denoted <i>Anp</i>IBP was recently isolated from a cold-adapted fungus, <i>Antarctomyces psychrot...
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MDPI AG
2020-05-01
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| Series: | Biomolecules |
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| Online Access: | https://www.mdpi.com/2218-273X/10/5/759 |
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| author | Akari Yamauchi Tatsuya Arai Hidemasa Kondo Yuji C. Sasaki Sakae Tsuda |
| author_facet | Akari Yamauchi Tatsuya Arai Hidemasa Kondo Yuji C. Sasaki Sakae Tsuda |
| author_sort | Akari Yamauchi |
| collection | DOAJ |
| description | Many microbes that survive in cold environments are known to secrete ice-binding proteins (IBPs). The structure–function relationship of these proteins remains unclear. A microbial IBP denoted <i>Anp</i>IBP was recently isolated from a cold-adapted fungus, <i>Antarctomyces psychrotrophicus</i>. The present study identified an orbital illumination (prism ring) on a globular single ice crystal when soaked in a solution of fluorescent <i>Anp</i>IBP, suggesting that <i>Anp</i>IBP binds to specific water molecules located in the ice prism planes. In order to examine this unique ice-binding mechanism, we carried out X-ray structural analysis and mutational experiments. It appeared that <i>Anp</i>IBP is made of 6-ladder β-helices with a triangular cross section that accompanies an “ice-like” water network on the ice-binding site. The network, however, does not exist in a defective mutant. <i>Anp</i>IBP has a row of four unique hollows on the IBS, where the distance between the hollows (14.7 Å) is complementary to the oxygen atom spacing of the prism ring. These results suggest the structure of <i>Anp</i>IBP is fine-tuned to merge with the ice–water interface of an ice crystal through its polygonal water network and is then bound to a specific set of water molecules constructing the prism ring to effectively halt the growth of ice. |
| first_indexed | 2024-03-10T19:51:18Z |
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| institution | Directory Open Access Journal |
| issn | 2218-273X |
| language | English |
| last_indexed | 2024-03-10T19:51:18Z |
| publishDate | 2020-05-01 |
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| record_format | Article |
| series | Biomolecules |
| spelling | doaj.art-26e9c8058b1d447c94f56c5eab55d98a2023-11-20T00:18:38ZengMDPI AGBiomolecules2218-273X2020-05-0110575910.3390/biom10050759An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism PlanesAkari Yamauchi0Tatsuya Arai1Hidemasa Kondo2Yuji C. Sasaki3Sakae Tsuda4Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, JapanGraduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, JapanGraduate School of Life Science, Hokkaido University, Sapporo 060-0810, JapanGraduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, JapanGraduate School of Life Science, Hokkaido University, Sapporo 060-0810, JapanMany microbes that survive in cold environments are known to secrete ice-binding proteins (IBPs). The structure–function relationship of these proteins remains unclear. A microbial IBP denoted <i>Anp</i>IBP was recently isolated from a cold-adapted fungus, <i>Antarctomyces psychrotrophicus</i>. The present study identified an orbital illumination (prism ring) on a globular single ice crystal when soaked in a solution of fluorescent <i>Anp</i>IBP, suggesting that <i>Anp</i>IBP binds to specific water molecules located in the ice prism planes. In order to examine this unique ice-binding mechanism, we carried out X-ray structural analysis and mutational experiments. It appeared that <i>Anp</i>IBP is made of 6-ladder β-helices with a triangular cross section that accompanies an “ice-like” water network on the ice-binding site. The network, however, does not exist in a defective mutant. <i>Anp</i>IBP has a row of four unique hollows on the IBS, where the distance between the hollows (14.7 Å) is complementary to the oxygen atom spacing of the prism ring. These results suggest the structure of <i>Anp</i>IBP is fine-tuned to merge with the ice–water interface of an ice crystal through its polygonal water network and is then bound to a specific set of water molecules constructing the prism ring to effectively halt the growth of ice.https://www.mdpi.com/2218-273X/10/5/759ice-binding proteinantifreeze proteinascomycetethermal hysteresisfluorescence-based ice plane affinitypolygonal waters |
| spellingShingle | Akari Yamauchi Tatsuya Arai Hidemasa Kondo Yuji C. Sasaki Sakae Tsuda An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes Biomolecules ice-binding protein antifreeze protein ascomycete thermal hysteresis fluorescence-based ice plane affinity polygonal waters |
| title | An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes |
| title_full | An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes |
| title_fullStr | An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes |
| title_full_unstemmed | An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes |
| title_short | An Ice-Binding Protein from an Antarctic Ascomycete Is Fine-Tuned to Bind to Specific Water Molecules Located in the Ice Prism Planes |
| title_sort | ice binding protein from an antarctic ascomycete is fine tuned to bind to specific water molecules located in the ice prism planes |
| topic | ice-binding protein antifreeze protein ascomycete thermal hysteresis fluorescence-based ice plane affinity polygonal waters |
| url | https://www.mdpi.com/2218-273X/10/5/759 |
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