1UZ2
The Cys121Ser Mutant of Beta-Lactoglobulin
Summary for 1UZ2
| Entry DOI | 10.2210/pdb1uz2/pdb |
| Related | 1B0O 1B8E 1BEB 1BSO 1BSQ 1BSY 1CJ5 1DV9 1GX8 1GX9 1GXA 1MFH 1QG5 2BLG 3BLG |
| Descriptor | BETA-LACTOGLOBULIN (2 entities in total) |
| Functional Keywords | lipocalin, beta-barrel, transport protein, milk, whey retinol-binding, allergen |
| Biological source | BOS TAURUS (CATTLE) |
| Total number of polymer chains | 1 |
| Total formula weight | 18371.20 |
| Authors | McNae, I.,Jayat, D.,Haertle, T.,Holt, C.,Sawyer, L. (deposition date: 2004-03-03, release date: 2004-05-20, Last modification date: 2024-11-13) |
| Primary citation | 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 Cited by 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: 15147215DOI: 10.1021/bi0362469 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.95 Å) |
Structure validation
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