1UZ2

The Cys121Ser Mutant of Beta-Lactoglobulin

1UZ2 の概要

• エントリーDOI: 10.2210/pdb1uz2/pdb
• 関連するPDBエントリー: 1B0O 1B8E 1BEB 1BSO 1BSQ 1BSY 1CJ5 1DV9 1GX8 1GX9 1GXA 1MFH 1QG5 2BLG 3BLG
• 分子名称: BETA-LACTOGLOBULIN (2 entities in total)
• 機能のキーワード: lipocalin, beta-barrel, transport protein, milk, whey retinol-binding, allergen
• 由来する生物種: BOS TAURUS (CATTLE)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 18371.20

構造登録者

McNae, I.,Jayat, D.,Haertle, T.,Holt, C.,Sawyer, L. (登録日: 2004-03-03, 公開日: 2004-05-20, 最終更新日: 2024-11-13)

主引用文献

Jayat, D.,Gaudin, J.C.,Chobert, J.M.,Burova, T.V.,Holt, C.,McNae, I.,Sawyer, L.,Haertle, T.
A recombinant C121S mutant of bovine beta-lactoglobulin is more susceptible to peptic digestion and to denaturation by reducing agents and heating.
Biochemistry, 43:6312-6321, 2004

PubMed Abstract: The lipocalin beta-lactoglobulin (BLG) is the major whey protein of bovine milk and is homodimeric at physiological conditions. Each monomer contains two disulfide bonds and one cysteine at position 121 (C121). This free thiol plays an important role in the heat-induced aggregation of BLG and, possibly, in its conformational stability. We describe here the expression in the yeast Pichia pastoris of a mutant bovine BLG, in which C121 was changed into Ser (C121S). Circular dichroism and high-performance liquid chromatography experiments, together with the X-ray crystal structure, show that the C121S mutant retains a nativelike fold at both neutral and acid pH. The mutation completely blocks the irreversible aggregation induced by heat treatment at 90 degrees C. Compared to the recombinant wild-type protein, the mutant is less stable to temperature and disulfide reducing agents and is much more sensitive to peptic digestion. Moreover, its affinity for 1-anilino-8-naphthalenesulfonate is increased at neutral and acid pH. We suggest that the stability of the protein arising from the hydrophobic effect is reduced by the C121S mutation so that unfolded or partially unfolded states are more favored.

PubMed: 15147215
DOI: 10.1021/bi0362469

実験手法

X-RAY DIFFRACTION (1.95 Å)