Structural highlights
Publication Abstract from PubMedPrevious attempts to crystallize mammalian gammaS-crystallin were unsuccessful. Native L16 chicken gammaS crystallized avidly while the Q16 mutant did not. The X-ray structure for chicken gammaS at 2.3 A resolution shows the canonical structure of the superfamily plus a well-ordered N arm aligned with a beta sheet of a neighboring N domain. L16 is also in a lattice contact, partially shielded from solvent. Unexpectedly, the major lattice contact matches a conserved interface (QR) in the multimeric beta-crystallins. QR shows little conservation of residue contacts, except for one between symmetry-related tyrosines, but molecular dipoles for the proteins with QR show striking similarities while other gamma-crystallins differ. In gammaS, QR has few hydrophobic contacts and features a thin layer of tightly bound water. The free energy of QR is slightly repulsive and analytical ultracentrifugation confirms no dimerization in solution. The lattice contacts suggest how gamma-crystallins allow close packing without aggregation in the crowded environment of the lens. Crystal Structure of Chicken gammaS-Crystallin Reveals Lattice Contacts with Implications for Function in the Lens and the Evolution of the betagamma-Crystallins.,Sagar V, Chaturvedi SK, Schuck P, Wistow G Structure. 2017 Jul 5;25(7):1068-1078.e2. doi: 10.1016/j.str.2017.05.015. Epub, 2017 Jun 22. PMID:28648607[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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