Temperature-Dependent Interactions Explain Normal and Inverted Solubility in a γD-Crystallin Mutant.

Journal Article (Journal Article)

Protein crystal production is a major bottleneck in the structural characterization of proteins. To advance beyond large-scale screening, rational strategies for protein crystallization are crucial. Understanding how chemical anisotropy (or patchiness) of the protein surface, due to the variety of amino-acid side chains in contact with solvent, contributes to protein-protein contact formation in the crystal lattice is a major obstacle to predicting and optimizing crystallization. The relative scarcity of sophisticated theoretical models that include sufficient detail to link collective behavior, captured in protein phase diagrams, and molecular-level details, determined from high-resolution structural information, is a further barrier. Here, we present two crystal structures for the P23T + R36S mutant of γD-crystallin, each with opposite solubility behavior: one melts when heated, the other when cooled. When combined with the protein phase diagram and a tailored patchy particle model, we show that a single temperature-dependent interaction is sufficient to stabilize the inverted solubility crystal. This contact, at the P23T substitution site, relates to a genetic cataract and reveals at a molecular level the origin of the lowered and retrograde solubility of the protein. Our results show that the approach employed here may present a productive strategy for the rationalization of protein crystallization.

Full Text

Duke Authors

Cited Authors

  • Khan, AR; James, S; Quinn, MK; Altan, I; Charbonneau, P; McManus, JJ

Published Date

  • September 2019

Published In

Volume / Issue

  • 117 / 5

Start / End Page

  • 930 - 937

PubMed ID

  • 31422822

Pubmed Central ID

  • PMC6731388

Electronic International Standard Serial Number (EISSN)

  • 1542-0086

International Standard Serial Number (ISSN)

  • 0006-3495

Digital Object Identifier (DOI)

  • 10.1016/j.bpj.2019.07.019

Language

  • eng