2018年5月22日
Polypentagonal ice-like water networks emerge solely in an activity-improved variant of ice-binding protein
Proceedings of the National Academy of Sciences of the United States of America
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- 巻
- 115
- 号
- 21
- 開始ページ
- 5456
- 終了ページ
- 5461
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1073/pnas.1800635115
- 出版者・発行元
- National Academy of Sciences
Polypentagonal water networks were recently observed in a protein capable of binding to ice crystals, or ice-binding protein (IBP). To examine such water networks and clarify their role in ice-binding, we determined X-ray crystal structures of a 65-residue defective isoform of a Zoarcidae-derived IBP (wild type, WT) and its five single mutants (A20L, A20G, A20T, A20V, and A20I). Polypentagonal water networks composed of ∼50 semiclathrate waters were observed solely on the strongest A20I mutant, which appeared to include a tetrahedral water cluster exhibiting a perfect position match to the (1010) first prism plane of a single ice crystal. Inclusion of another symmetrical water cluster in the polypentagonal network showed a perfect complementarity to the waters constructing the (2021) pyramidal ice plane. The order of ice-binding strength was A20L <
A20G <
WT <
A20T <
A20V <
A20I, where the top three mutants capable of binding to the first prism and the pyramidal ice planes commonly contained a bifurcated γ-CH3 group. These results suggest that a fine-tuning of the surface of Zoarcidae-derived IBP assisted by a side-chain group regulates the holding property of its polypentagonal water network, the function of which is to freeze the host protein to specific ice planes.
A20G <
WT <
A20T <
A20V <
A20I, where the top three mutants capable of binding to the first prism and the pyramidal ice planes commonly contained a bifurcated γ-CH3 group. These results suggest that a fine-tuning of the surface of Zoarcidae-derived IBP assisted by a side-chain group regulates the holding property of its polypentagonal water network, the function of which is to freeze the host protein to specific ice planes.
- リンク情報
- ID情報
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- DOI : 10.1073/pnas.1800635115
- ISSN : 1091-6490
- ISSN : 0027-8424
- ORCIDのPut Code : 44768444
- PubMed ID : 29735675
- SCOPUS ID : 85047356104