6NKQ
The structure of bovine beta-lactoglobulin in novel crystals grown at pH 3.8
Summary for 6NKQ
| Entry DOI | 10.2210/pdb6nkq/pdb |
| Descriptor | Beta-lactoglobulin, CALCIUM ION (3 entities in total) |
| Functional Keywords | milk, twinning, space group, whey protein, molecular replacement, tanford transition, unknown function |
| Biological source | Bos taurus (Bovine) |
| Total number of polymer chains | 6 |
| Total formula weight | 119465.44 |
| Authors | McPherson, A. (deposition date: 2019-01-07, release date: 2019-01-23, Last modification date: 2023-10-11) |
| Primary citation | Yeates, T.O.,McPherson, A. The structure of bovine beta-lactoglobulin in crystals grown at pH 3.8 exhibiting novel threefold twinning. Acta Crystallogr.,Sect.F, 75:640-645, 2019 Cited by PubMed Abstract: Bovine β-lactoglobulin was crystallized from 3 M NaCl buffered at pH 3.8 with sodium citrate as thick hexagonal prisms of greater than 1 mm in edge length. Analyses of the X-ray diffraction intensities using three different current algorithms were unanimous in specifying the space group to be P622, with unit-cell dimensions a = b = 75.47, c = 140.79 Å. No progress could be made, however, towards an acceptable solution by molecular replacement using this symmetry. In the end, it was found that the true space group was C222, a subgroup of P622, with a = 65.89, b = 114.12, c = 140.51 Å, with the apparent 622 symmetry arising from an unusual threefold or tritohedral twinning. An assembly based on a model of the protein in another crystal form (PDB entry 1beb) containing three molecules in the asymmetric unit was refined to 2.3 Å resolution with a final R factor of 0.23 and R of 0.26. NCS restraints were maintained throughout. For the most part, the molecules found in this crystal form are virtually the same as in PDB entry 1beb, although there are numerous local variations, particularly in loop elements, rotamer conformation differences and some alterations, including additions, at the termini. PubMed: 31584012DOI: 10.1107/S2053230X1901224X PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.3 Å) |
Structure validation
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