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Publication Abstract from PubMed

Protein conformational switches or allosteric proteins play a key role in the regulation of many essential biological pathways. Nonetheless, the implementation of protein conformational switches in protein design applications has proven challenging, with only a few known examples that are not derivatives of naturally occurring allosteric systems. We have discovered that the domain swapped (DS) dimer of hCRBPII undergoes a large and robust conformational change upon retinal binding, making it a potentially powerful template for the design of protein conformational switches. Atomic resolution structures of the apo- and holo- forms illuminate a simple, mechanical mechanism involving sterically driven torsion angle flipping of two residues that drive the motion. We further demonstrate that the con-formational "readout" can be altered by addition of cross-domain disulfide bonds, also visualized at atomic resolution. Finally, as a proof of principle, we have created an allosteric metal binding site in the DS dimer, where ligand binding results in a reversible five-fold loss of metal binding affinity. The high resolution structure of the metal-bound variant illustrates a well-formed metal binding site at the inter-face of the two domains of the DS dimer, and confirms the design strategy for allosteric regulation.

Engineering the hCRBPII domain-swapped dimer into a new class of protein switches.,Ghanbarpour A, Pinger C, Esmatpour Salmani R, Assar Z, Santos EM, Nosrati M, Pawlowski K, Spence D, Vasileiou C, Jin X, Borhan B, Geiger JH J Am Chem Soc. 2019 Sep 26. doi: 10.1021/jacs.9b04664. PMID:31557439^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.