1uz2
From Proteopedia
THE CYS121SER MUTANT OF BETA-LACTOGLOBULIN
Overview
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.
About this Structure
1UZ2 is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
A recombinant C121S mutant of bovine beta-lactoglobulin is more susceptible to peptic digestion and to denaturation by reducing agents and heating., Jayat D, Gaudin JC, Chobert JM, Burova TV, Holt C, McNae I, Sawyer L, Haertle T, Biochemistry. 2004 May 25;43(20):6312-21. PMID:15147215 Page seeded by OCA on Sat May 3 11:53:18 2008
Categories: Bos taurus | Single protein | Haertle, T. | Holt, C. | Jayat, D. | Mcnae, I. | Sawyer, L. | Allergen | Beta-barrel | Lipocalin | Milk | Transport protein | Whey retinol-binding
