3P4G

X-ray crystal structure of a hyperactive, Ca2+-dependent, beta-helical antifreeze protein from an Antarctic bacterium

3P4G の概要

• エントリーDOI: 10.2210/pdb3p4g/pdb
• 分子名称: Antifreeze protein, CALCIUM ION, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: right-handed ca2+-binding beta-helix, antifreeze protein
• 由来する生物種: Marinomonas primoryensis
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 135734.22

構造登録者

Garnham, C.P.,Campbell, R.L.,Davies, P.L. (登録日: 2010-10-06, 公開日: 2011-04-27, 最終更新日: 2024-02-21)

主引用文献

Garnham, C.P.,Campbell, R.L.,Davies, P.L.
Anchored clathrate waters bind antifreeze proteins to ice.
Proc.Natl.Acad.Sci.USA, 108:7363-7367, 2011

PubMed Abstract: The mechanism by which antifreeze proteins (AFPs) irreversibly bind to ice has not yet been resolved. The ice-binding site of an AFP is relatively hydrophobic, but also contains many potential hydrogen bond donors/acceptors. The extent to which hydrogen bonding and the hydrophobic effect contribute to ice binding has been debated for over 30 years. Here we have elucidated the ice-binding mechanism through solving the first crystal structure of an Antarctic bacterial AFP. This 34-kDa domain, the largest AFP structure determined to date, folds as a Ca(2+)-bound parallel beta-helix with an extensive array of ice-like surface waters that are anchored via hydrogen bonds directly to the polypeptide backbone and adjacent side chains. These bound waters make an excellent three-dimensional match to both the primary prism and basal planes of ice and in effect provide an extensive X-ray crystallographic picture of the AFPice interaction. This unobstructed view, free from crystal-packing artefacts, shows the contributions of both the hydrophobic effect and hydrogen bonding during AFP adsorption to ice. We term this mode of binding the "anchored clathrate" mechanism of AFP action.

PubMed: 21482800
DOI: 10.1073/pnas.1100429108

実験手法

X-RAY DIFFRACTION (1.7 Å)