Semen is the main vector for HIV transmission and contains amyloid fibrils that enhance viral infection. Available microbicides that target viral components have proven largely ineffective in preventing sexual virus transmission. In this study, we establish that CLR01, a ‘molecular tweezer’ specific for lysine and arginine residues, inhibits the formation of infectivity-enhancing seminal amyloids and remodels preformed fibrils. Moreover, CLR01 abrogates semen-mediated enhancement of viral infection by preventing the formation of virion–amyloid complexes and by directly disrupting the membrane integrity of HIV and other enveloped viruses. We establish that CLR01 acts by binding to the target lysine and arginine residues rather than by a non-specific, colloidal mechanism. CLR01 counteracts both host factors that may be important for HIV transmission and the pathogen itself. These combined anti-amyloid and antiviral activities make CLR01 a promising topical microbicide for blocking infection by HIV and other sexually transmitted viruses.DOI:
http://dx.doi.org/10.7554/eLife.05397.001
Protein regions that are involved
in protein–protein interactions
(PPIs) very often display a high degree of intrinsic disorder, which
is reduced during the recognition process. A prime example is binding
of the rigid 14-3-3 adapter proteins to their numerous partner proteins,
whose recognition motifs undergo an extensive disorder-to-order transition.
In this context, it is highly desirable to control this entropy-costly
process using tailored stabilizing agents. This study reveals how
the molecular tweezer CLR01 tunes the 14-3-3/Cdc25CpS216 protein–protein
interaction. Protein crystallography, biophysical affinity determination
and biomolecular simulations unanimously deliver a remarkable finding:
a supramolecular “Janus” ligand can bind simultaneously
to a flexible peptidic PPI recognition motif and to a well-structured
adapter protein. This binding fills a gap in the protein–protein
interface, “freezes” one of the conformational states
of the intrinsically disordered Cdc25C protein partner and enhances
the apparent affinity of the interaction. This is the first structural
and functional proof of a supramolecular ligand targeting a PPI interface
and stabilizing the binding of an intrinsically disordered recognition
motif to a rigid partner protein.
Molecular tweezers for lysine and arginine select a few residues on a protein surface and by their unique complexation mode disrupt a critical protein-protein interaction. Detailed structural information was gained by NMR experiments, strongly supported by QM/MM calculations and further substantiated by ITC, fluorescence anisotropy, ELISA and bio-layer-interference studies.
Nichtkovalente Wechselwirkungen zwischen Proteinen steuern viele Prozesse im menschlichen Körper. Maßgeschneiderte künstliche Liganden binden Proteine, hemmen so Enzyme oder machen Viren weniger infektiös.
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