Multivalent Cluster Nanomolecules for Inhibiting Protein–Protein Interactions

Abstract

Multivalent protein−protein interactions serve central roles in many essential biological processes, ranging from cell signaling and adhesion to pathogen recognition. Uncovering the rules that govern these intricate interactions is important not only to basic biology and chemistry but also to the applied sciences where researchers are interested in developing molecules to promote or inhibit these interactions.Here we report the synthesis and application of atomically precise inorganic cluster nanomolecules consisting of an inorganic core and a covalently linked densely packed layer of saccharides. These hybrid agents are stable under biologically relevant conditions and exhibit multivalent binding capabilities, which enable us to study the complex interactions between glycosylated structures and a dendritic cell lectin receptor. Importantly, we find that subtle changes in the molecular structure lead to significant differences in the nanomolecule's proteinbinding properties. Furthermore, we demonstrate an example of using these hybrid nanomolecules to effectively inhibit protein−protein interactions in a human cell line. Ultimately, this work reveals an intricate interplay between the structural design of multivalent agents and their biological activities toward protein surfaces.

An Organometallic Strategy for Assembling Atomically Precise Hybrid Nanomaterials

“…SPR binding data reveal that [ 20 ] 2– exhibits an enhanced dose-dependent avidity ( K D = 3.7 μM, Figure e) toward DC-SIGN when compared with the negligible responses observed for the d -mannose monosaccharide and PEGylated controls ([ 8 ] 2– ) at significantly higher mass concentrations (SI section 6.3). These findings support the multivalent nature of the binding interaction between [ 20 ] 2– and DC-SIGN and agree well with the MD simulation performed for this system (Figure d, SI section S8), which displays the specific binding in atomic detail. The calculated K D value is also in good agreement with that of a related mannose-coated multivalent gold nanoparticle bearing 25 surface sugars that binds DC-SIGN with high affinity ( K D = 0.974 μM) …”

Gold(III) Aryl Complexes as Reagents for Constructing Hybrid Peptide-Based Assemblies via Cysteine S-Arylation

“…Treatment of in situ -generated [ 4 ]­[SbF 6 ] 11 with GSH in a TRIS-buffered DMF/H 2 O (50:50 v/v) solution resulted in a gradual color change from dark purple to colorless over the course of 15 min, which is indicative of a single-electron reduction of the cluster core from the radical monoanionic to the diamagnetic, dianionic charge state. Cluster reduction has been previously observed during thiol conjugation reactions of similar systems and is consistent with the reducing capacity of thiolate species. ,, Conversion of [ 4 ] 11+ to the 12-fold-substituted GSH bioconjugate ([ 4a ] 2– ) was assessed by LC-MS analysis of the reaction mixture. The crude product was purified by reversed-phase HPLC, and the LC-MS data confirming the purity and identity of the resulting bioconjugate are displayed in Figure D.…”

“…The water-soluble product was purified by size-exclusion chromatography, which afforded the cluster conjugate as an air-stable solid that was characterized by 11 B and 1 H NMR spectroscopy (SI Section S2.3.7) and ESI-MS(−). The present work serves as an important proof-of-principle demonstration that the densely functionalized, organometallic [ 4 ] 11+ cluster can serve as a competent synthon for the preparation of highly complex, yet well-defined hybrid nanoassemblies and provides a versatile strategy for the synthesis of new, biocompatible multivalent systems. ,,,,− …”

“…Through functionalization of each boron vertex of an icosahedral B 12 core with organometallic (P,N)­Au­(III)­ArCl fragments, the boron-cluster-based approach to the synthesis of multivalent clusters provides a systematic method of preparing biologically relevant hybrid nanoassemblies through Au­(III)-mediated C–S bond-forming conjugation reactions. We have previously shown that dodecaborate clusters perfunctionalized with biologically relevant thiolate surface ligands (saccharides, peptides, poly­(ethylene glycol) polymers) exhibit high structural stability under biologically relevant conditions due to their full covalency, which consequently provided an appropriate platform for us to interrogate their multivalent binding interactions with complex protein targets. ,− While many other nanoscale assemblies display multivalent binding capabilities, such systems are seldom atomically precise, − which has driven research efforts focused on developing versatile assembly processes that provide access to well-defined and programmable systems. With a constantly evolving field of nanobiotechnology dedicated to addressing these challenges, we were motivated to expand upon the synthetic capabilities and utility of the boron-cluster-based platform by employing the present (P,N)­Au­(III)-mediated conjugation strategy to assemble atomically precise, robust hybrid nanoclusters with multivalent binding capabilities.…”

Identification of hot regions in hub protein–protein interactions by clustering and PPRA optimization

“…Proteins perform their various biological functions by interacting with other proteins, nucleic acids or small molecules [ 1 , 2 ]. Recognizing the interaction of proteins can reveal the mechanism of protein activities and promote the development of biotechnology and life science [ 3 , 4 ].…”