1DV9
STRUCTURAL CHANGES ACCOMPANYING PH-INDUCED DISSOCIATION OF THE B-LACTOGLOBULIN DIMER
Summary for 1DV9
| Entry DOI | 10.2210/pdb1dv9/pdb |
| Related | 1B0O 1BEB 1BSO 1BSY 2BLG 3BLG |
| Descriptor | BETA-LACTOGLOBULIN (1 entity in total) |
| Functional Keywords | beta-lactoglobulin, beta-barrel, low ph structure, triple resonance experiments, transport protein |
| Biological source | Bos taurus (cattle) |
| Total number of polymer chains | 1 |
| Total formula weight | 18395.20 |
| Authors | Uhrinova, S.,Smith, M.H.,Jameson, G.B.,Uhrin, D.,Sawyer, L.,Barlow, P.N. (deposition date: 2000-01-20, release date: 2000-02-09, Last modification date: 2024-11-13) |
| Primary citation | Uhrinova, S.,Smith, M.H.,Jameson, G.B.,Uhrin, D.,Sawyer, L.,Barlow, P.N. Structural changes accompanying pH-induced dissociation of the beta-lactoglobulin dimer. Biochemistry, 39:3565-3574, 2000 Cited by PubMed Abstract: We have used NMR spectroscopy to determine the three-dimensional (3D) structure, and to characterize the backbone dynamics, of a recombinant version of bovine beta-lactoglobulin (variant A) at pH 2. 6, where the protein is a monomer. The structure of this low-pH form of beta-lactoglobulin is very similar to that of a subunit within the dimer at pH 6.2. The root-mean-square deviation from the pH 6.2 (crystal) structure, calculated for backbone atoms of residues 6-160, is approximately 1.3 A. Differences arise from the orientation, with respect to the calyx, of the A-B and C-D loops, and of the flanking three-turn alpha-helix. The hydrophobic cavity within the calyx is retained at low pH. The E-F loop (residues 85-90), which moves to occlude the opening of the cavity over the pH range 7.2-6.2, is in the "closed" position at pH 2.6, and the side chain of Glu89 is buried. We also carried out measurements of (15)N T(1)s and T(2)s and (1)H-(15)N heteronuclear NOEs at pH 2.6 and 37 degrees C. Although the residues of the E-F loop (residues 86-89) have the highest crystallographic B-factors, the conformation of this loop is reasonably well defined by the NMR data, and its backbone is not especially mobile on the pico- to nanosecond time scale. Several residues (Ser21, Lys60, Ala67, Leu87, and Glu112) exhibit large ratios of T(1) to T(2), consistent with conformational exchange on a micro- to millisecond time scale. The positions of these residues in the 3D structure of beta-lactoglobulin are consistent with a role in modulating access to the hydrophobic cavity. PubMed: 10736155DOI: 10.1021/bi992629o PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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