5B5H

Hydrophobic ice-binding site confer hyperactivity on antifreeze protein from a snow mold fungus

5B5H の概要

• エントリーDOI: 10.2210/pdb5b5h/pdb
• 分子名称: Antifreeze protein, SULFATE ION, SODIUM ION, ... (4 entities in total)
• 機能のキーワード: right-handed beta-helix, beta-solenoid, antifreeze protein, ice-binding protein
• 由来する生物種: Typhula ishikariensis
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 22362.34

構造登録者

Cheng, J.,Hanada, Y.,Miura, A.,Tsuda, S.,Kondo, H. (登録日: 2016-05-06, 公開日: 2016-09-28, 最終更新日: 2023-11-08)

主引用文献

Cheng, J.,Hanada, Y.,Miura, A.,Tsuda, S.,Kondo, H.
Hydrophobic ice-binding sites confer hyperactivity of an antifreeze protein from a snow mold fungus.
Biochem.J., 473:4011-4026, 2016

PubMed Abstract: Snow mold fungus, Typhula ishikariensis, secretes seven antifreeze protein isoforms (denoted TisAFPs) that assist in the survival of the mold under snow cover. Here, the X-ray crystal structure of a hyperactive isoform, TisAFP8, at 1.0 Å resolution is presented. TisAFP8 folds into a right-handed β-helix accompanied with a long α-helix insertion. TisAFP8 exhibited significantly high antifreeze activity that is comparable with other hyperactive AFPs, despite its close structural and sequence similarity with the moderately active isoform TisAFP6. A series of mutations introduced into the putative ice-binding sites (IBSs) in the β-sheet and adjacent loop region reduced antifreeze activity. A double-mutant A20T/A212S, which comprises a hydrophobic patch between the β-sheet and loop region, caused the greatest depression of antifreeze activity of 75%, when compared with that of the wild-type protein. This shows that the loop region is involved in ice binding and hydrophobic residues play crucial functional roles. Additionally, bound waters around the β-sheet and loop region IBSs were organized into an ice-like network and can be divided into two groups that appear to mediate separately TisAFP and ice. The docking model of TisAFP8 with the basal plane via its loop region IBS reveals a better shape complementarity than that of TisAFP6. In conclusion, we present new insights into the ice-binding mechanism of TisAFP8 by showing that a higher hydrophobicity and better shape complementarity of its IBSs, especially the loop region, may render TisAFP8 hyperactive to ice binding.

PubMed: 27613857
DOI: 10.1042/BCJ20160543

実験手法

X-RAY DIFFRACTION (1 Å)