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15 results on '"Yamauchi, Akari"'

4. The ice-binding and cell-protection function of insect-derived antifreeze protein

Author

Yamauchi, Akari and Tsuda, Sakae

Subjects
Dorcus hopei binodulosus, cell-protection, オオクワガタ, Cold-adaptation, thermal hysteresis, 熱ヒステリシス, 低温適応, 不凍タンパク質, 細胞保護, antifreeze protein
Abstract

第一章：変温動物, 一部の生物は氷点下にもなる低温環境に生息し，凍結や低体温のリスクに晒されるにも関わらず，生命活動を維持することができる．なぜこれらの生物は凍結障害や低温障害を受けずに生命活動を維持できるのだろうか？不凍タンパク質（Antifreeze protein：AFP）は寒冷な環境に生息する様々な魚類・昆虫・植物・微生物等で見出される低温適応タンパク質の1つである．AFPは氷に結合しその成長を抑制する機能（氷結晶結合機能）と，細胞膜に結合し低温障害から細胞を保護する機能（細胞保護機能）を有する．AFPの両機能は低温下におけるこれら生物の生命維持に重要な役割を果たすと考えられている．本稿では，昆虫由来AFPを中心に，AFPの氷結晶結合機能と細胞保護機能について紹介する．, Some organisms can be alive in cold environment even below 0℃, in spite of the risk of freezing and hypothermia. How are these organisms able to maintain their life without freezing injury and cold damage? Antifreeze proteins (AFPs) are one of cryoprotective proteins found in various cold-adapted fish, insects, plants, and microorganisms living in cold environments. AFPs can bind to single ice crystal and inhibit its growth (ice-binding function). Moreover, AFPs can prolong the life-time of mammalian cells at low temperature through its binding to lipid bilayer (cell-protection function). Both functions of AFPs are thought to play important roles in sustaining the life of these organisms at low temperatures. In this paper, we introduce the ice-binding and cell-protection functions of insect-derived AFP.

Published
2023

12. Fish-Derived Antifreeze Proteins and Antifreeze Glycoprotein Exhibit a Different Ice-Binding Property with Increasing Concentration

Author

1000070211381, Tsuda, Sakae, Yamauchi, Akari, Khan, N. M. -Mofiz Uddin, Arai, Tatsuya, Mahatabuddin, Sheikh, Miura, Ai, Kondo, Hidemasa, 1000070211381, Tsuda, Sakae, Yamauchi, Akari, Khan, N. M. -Mofiz Uddin, Arai, Tatsuya, Mahatabuddin, Sheikh, Miura, Ai, and Kondo, Hidemasa

Abstract

The concentration of a protein is highly related to its biochemical properties, and is a key determinant for its biotechnological applications. Antifreeze proteins (AFPs) and antifreeze glycoproteins (AFGPs) are structurally diverse macromolecules that are capable of binding to embryonic ice crystals below 0 degrees C, making them useful as protectants of ice-block formation. In this study, we examined the maximal solubility of native AFP I-III and AFGP with distilled water, and evaluated concentration dependence of their ice-binding property. Approximately 400 mg/mL (AFP I), 200 mg/mL (AFP II), 100 mg/mL (AFP III), and >1800 mg/mL (AFGP) of the maximal solubility were estimated, and among them AFGP's solubility is much higher compared with that of ordinary proteins, such as serum albumin (similar to 500 mg/mL). The samples also exhibited unexpectedly high thermal hysteresis values (2-3 degrees C) at 50-200 mg/mL. Furthermore, the analysis of fluorescence-based ice plane affinity showed that AFP II binds to multiple ice planes in a concentration-dependent manner, for which an oligomerization mechanism was hypothesized. The difference of concentration dependence between AFPs and AFGPs may provide a new clue to help us understand the ice-binding function of these proteins.

Published
2020

13. Fish-Derived Antifreeze Proteins and Antifreeze Glycoprotein Exhibit a Different Ice-Binding Property with Increasing Concentration

Author

Tsuda, Sakae, Yamauchi, Akari, Khan, N. M. -Mofiz Uddin, Arai, Tatsuya, Mahatabuddin, Sheikh, Miura, Ai, Kondo, Hidemasa, Tsuda, Sakae, Yamauchi, Akari, Khan, N. M. -Mofiz Uddin, Arai, Tatsuya, Mahatabuddin, Sheikh, Miura, Ai, and Kondo, Hidemasa

Abstract

The concentration of a protein is highly related to its biochemical properties, and is a key determinant for its biotechnological applications. Antifreeze proteins (AFPs) and antifreeze glycoproteins (AFGPs) are structurally diverse macromolecules that are capable of binding to embryonic ice crystals below 0 degrees C, making them useful as protectants of ice-block formation. In this study, we examined the maximal solubility of native AFP I-III and AFGP with distilled water, and evaluated concentration dependence of their ice-binding property. Approximately 400 mg/mL (AFP I), 200 mg/mL (AFP II), 100 mg/mL (AFP III), and >1800 mg/mL (AFGP) of the maximal solubility were estimated, and among them AFGP's solubility is much higher compared with that of ordinary proteins, such as serum albumin (similar to 500 mg/mL). The samples also exhibited unexpectedly high thermal hysteresis values (2-3 degrees C) at 50-200 mg/mL. Furthermore, the analysis of fluorescence-based ice plane affinity showed that AFP II binds to multiple ice planes in a concentration-dependent manner, for which an oligomerization mechanism was hypothesized. The difference of concentration dependence between AFPs and AFGPs may provide a new clue to help us understand the ice-binding function of these proteins.

Published
2020

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