A Bifunctional Spin Label for Ligand Recognition on Surfaces

Abstract

In situ monitoring of biomolecular recognition, especially at surfaces, still presents a significant technical challenge. Electron paramagnetic resonance (EPR) of biomolecules spin‐labeled with nitroxides can offer uniquely sensitive and selective insights into these processes, but new spin‐labeling strategies are needed. The synthesis and study of a bromoacrylaldehyde spin label (BASL), which features two attachment points with orthogonal reactivity is reported. The first examples of mannose and biotin ligands coupled to aqueous carboxy‐functionalized gold nanoparticles through a spin label are presented. EPR spectra were obtained for the spin‐labeled ligands both free in solution and attached to nanoparticles. The labels were recognized by the mannose‐binding lectin, Con A, and the biotin‐binding protein avidin‐peroxidase. Binding gave quantifiable changes in the EPR spectra from which binding profiles could be obtained that reflect the strength of binding in each case.

Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: I/theoretical design and properties

“…Also, in structural biology, it is relevant to study by EPR spin labeled proteins [9,10] introduced in model lipid bilayers membranes [11,12]. In the context of the development of new theranostic agents for nanomedicine, it is also relevant to study ligandprotein molecular recognition events occurring on surfaces by EPR, using for example, bifunctional spin labels [13]. As various nanotechnologies now allow to produce biological, chemical or physical samples with nanoscale thickness, one needs to perform sensitive surface EPR.…”

Spin Labeling of Surface Cysteines Using a Bromoacrylaldehyde Spin Label

“…BASL was prepared according to previous reports [ 36 ]. Briefly, 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy radical (4-oxo-TEMPO) was brominated and converted via Favorskii rearrangement to 4-bromo-3-carboxy-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yloxyl radical.…”

“…BASL has been recently used for spin labeling of bioactive ligands on gold nanoparticles [ 36 ]. Utilizing the bifunctional BA group, allowed reaction with a thiol by nucleophilic substitution of the bromine and reaction with an amine by reductive amination of the aldehyde.…”

C4‐Selective Synthesis of Vinyl Thiocyanates and Selenocyanates Through 3,4‐Dihalo‐2(5H)‐furanones

“…Thiocyanates have important biological activities and drug properties, such as antibacterial, anticancer, antiviral, etc Importantly, due to the presence of the active CN in SCN group, thiocyanate derivatives as versatile intermediates can be handily transformed to other significant compounds, such as trifluoromethyl sulfides, sulfonyl chlorides, thiols, thiocarbamates, sulfur‐containing heterocycles, disulfides, thioethers, etc. Hence, researchers around the world have made considerable efforts to develop efficient methods for the synthesis of thiocyanate derivatives, including aromatic and vinyl thiocyanate derivatives …”