DARPins: a true alternative to antibodies.
ABSTRACT Designed ankyrin repeat proteins (DARPins) are a promising class of non-immunoglobulin proteins that can offer advantages over antibodies for target binding in drug discovery and drug development. DARPins have been successfully used, for example, for the inhibition of kinases, proteases and drug-exporting membrane proteins. DARPins specifically targeting the cancer marker HER2 have also been generated and were shown to function in both in vitro diagnostics and in vivo tumor targeting. DARPins are ideally suited for in vivo imaging or delivery of toxins or other therapeutic payloads because of their favorable molecular properties, including small size and high stability. The low-cost production in bacteria and the rapid generation of many target-specific DARPins make the DARPin approach useful for drug discovery. Additionally, DARPins can be easily generated in multispecific formats, offering the potential to target an effector DARPin to a specific organ or to target multiple receptors with one molecule composed of several DARPins.
- SourceAvailable from: Maksym Tsytlonok[Show abstract] [Hide abstract]
ABSTRACT: Here, using single-molecule FRET, we reveal previously hidden conformations of the ankyrin-repeat domain of AnkyrinR, a giant adaptor molecule that anchors integral membrane proteins to the spectrin-actin cytoskeleton through simultaneous binding of multiple partner proteins. We show that the ankyrin repeats switch between high-FRET and low-FRET states, controlled by an unstructured "safety pin" or "staple" from the adjacent domain of AnkyrinR. Opening of the safety pin leads to unravelling of the ankyrin repeat stack, a process that will dramatically affect the relative orientations of AnkyrinR binding partners and, hence, the anchoring of the spectrin-actin cytoskeleton to the membrane. Ankyrin repeats are one of the most ubiquitous molecular recognition platforms in nature, and it is therefore important to understand how their structures are adapted for function. Our results point to a striking mechanism by which the order-disorder transition and, thereby, the activity of repeat proteins can be regulated. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.Structure 01/2015; 23(1):190-8. · 6.79 Impact Factor
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ABSTRACT: Designed ankyrin repeat proteins (DARPins) are valuable tools in both biochemistry and medicine. Herein we describe a rapid, simple method for the dual modification of DARPins by introduction of cysteine mutations at specific positions that results in a vast difference in their thiol nucleophilicity, allowing for clean sequential modification.Chemical Communications 04/2014; · 6.38 Impact Factor
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ABSTRACT: We developed a process to produce novel interactions between two previously unrelated proteins. This process selects protein scaffolds and designs protein interfaces that bind to a surface patch of interest on a target protein. Scaffolds with shapes complementary to the target surface patch were screened using an exhaustive computational search of the human proteome and optimized by directed evolution using phage display. This method was applied to successfully design scaffolds that bind to epidermal growth factor receptor (EGFR) domain II, the interface of EGFR dimerization, with high reactivity toward the target surface patch of EGFR domain II. One potential application of these tailor-made protein interactions is the development of therapeutic agents against specific protein targets.PLoS ONE 04/2014; 9(4):e92513. · 3.53 Impact Factor