Why a complementary analytical toolbox is essential for correct siRNA duplex content determination.

Small interfering RNAs (siRNAs) have emerged as a highly promising class of therapeutics, capable of effectively treating a wide range of indications, including previously challenging targets. To correctly characterize the duplex content of siRNA therapeutics, a careful design of the analytical conditions is required. This is due to the weak interactions governing the duplex formation and thermal stability of these double-stranded oligonucleotides.

Structure and Flexibility of Copper-Modified DNA G-Quadruplexes Investigated by F ENDOR Experiments at 34 GHz.

DNA G-quadruplexes (GQs) are of great interest due to their involvement in crucial biological processes such as telomerase maintenance and gene expression. Furthermore, they are reported as catalytically active DNAzymes and building blocks in bio-nanotechnology. GQs exhibit remarkable structural diversity and conformational heterogeneity, necessitating precise and reliable tools to unravel their structure-function relationships.

Duality Between Coronavirus Transmission and Air-Based Macroscopic Molecular Communication.

This contribution exploits the duality between a viral infection process and macroscopic air-based molecular communication. Airborne aerosol and droplet transmission through human respiratory processes is modeled as an instance of a multiuser molecular communication scenario employing respiratory-event-driven molecular variable-concentration shift keying. Modeling is aided by experiments that are motivated by a macroscopic air-based molecular communication testbed.

Precise Distance Measurements in DNA G-Quadruplex Dimers and Sandwich Complexes by Pulsed Dipolar EPR Spectroscopy.

DNA G-quadruplexes show a pronounced tendency to form higher-order structures, such as π-stacked dimers and aggregates with aromatic binding partners. Reliable methods for determining the structure of these non-covalent adducts are scarce. Here, we use artificial square-planar Cu(pyridine) complexes, covalently incorporated into tetramolecular G-quadruplexes, as rigid spin labels for detecting dimeric structures and measuring intermolecular Cu -Cu distances via pulsed dipolar EPR spectroscopy.

Heteroleptic Coordination Environments in Metal-Mediated DNA G-Quadruplexes.

The presence of metal centers with often highly conserved coordination environments is crucial for roughly half of all proteins, having structural, regulatory, or enzymatic function. To understand and mimic the function of metallo-enzymes, bioinorganic chemists pursue the challenge of synthesizing model compounds with well-defined, often heteroleptic metal sites. Recently, we reported the design of tailored homoleptic coordination environments for various transition metal cations based on unimolecular DNA G-quadruplex structures, templating the regioselective positioning of imidazole ligandosides .

Structure-Property Relationships in Cu -Binding Tetramolecular G-Quadruplex DNA.

A series of artificial metal-base tetrads composed of a Cu cation coordinating to four pyridines, covalently attached to the ends of tetramolecular G-quadruplex DNA strands [L d(G )] (L =ligand derivatives), was systematically studied. Structurally, the square-planar [Cu(pyridine) ] complex behaves analogously to the canonical guanine quartet. Copper coordination to all studied ligand derivatives was found to increase G-quadruplex thermodynamic stability, tolerating a great variety of ligand linker lengths (1-5 atoms) and thus demonstrating the robustness of the chosen ligand design.

Syntheses, Structures, and Complexation Studies of Tris(organostannyl)methane Derivatives.

The syntheses of tris(organostannyl)methanes HC(SnX Ph) (, =0; , =1, X=I; , =1, X =F; , =1, X=Cl; , =1, X=OAc; , =2, X=I; , =2, X=Cl) and the organostannate complexes EtN[HC(SnIPh)⋅F] (), PhP[HC(SnClPh)⋅Cl] (), and [PhP][HC(SnClPh)⋅2 Cl] () are reported. The compounds were characterized by H, C, F, and Sn NMR spectroscopy, IR spectroscopy, electrospray mass spectrometry, and (with the exception of ) single-crystal X-ray diffraction analysis. From the reaction between and AgClO resulted the unprecedented hexanuclear organotin oxocluster [HC{Sn(ClO)Ph}Sn(OH)Ph] (), the molecular structure of which was elucidated by using X-ray crystallography.