Biology subjects

Reiter, C.

Publications and source records attributed to Reiter, C..

3 recordsLinked to original sources

bioRxiv2025

Pushing Sensitivity and Specificity Limits in Native Structural Biology: 19F Multinuclear Dynamic Nuclear Polarization with Magic Angle Spinning

Understanding protein structures and their interactions within natural cellular environments is essential for deciphering cellular processes and advancing therapeutic development. Obtaining atomic-level information about protein structural changes in cellular contexts poses a significant challenge. Here, we introduce a 19F-based, 1H-assisted dynamic nuclear polarization (DNP) magic angle spinning (MAS) NMR approach that offers exceptionally high sensitivity and specificity, enabling background-free detection of target proteins in mammalian cells for atomic-level structural analysis. We demonstrate this methodology in A2780 cells for the human Cyclophilin A (CypA) protein with a single fluorine atom incorporated in the sole tryptophan residue. We achieved significant sensitivity gains through 1H-19F cross-polarization (CP), with subsequent 19F-13C double CP providing unique structural information. Remarkably, using 1H-19F13C magnetization transfer allowed selective detection of 13C signals from CypA residues up to 6 [A] away from the fluorine label. Taken together, our study establishes a framework for investigating protein structure, dynamics, and interactions in mammalian cells by DNP MAS NMR.

biophysics↗

bioRxiv2025

Is Language a Mechanical Signal? Cytoskeletal Responses to Speech in Yeast

What if vocal language were not only a medium for human communication but a vibrational force that leaves structural traces in living cells? This study explores how audible sound, particularly the structured elements of human speech, affects the cytoskeleton of Saccharomyces cerevisiae. Using a direct-contact acoustic system, we exposed yeast to distinct sound types: tonal vibrations, broadband noise, and consonant phonemes. Fluorescence microscopy revealed that tonal stimuli with coherent low-frequency patterns enhanced actin polymerization and shmoo formation, both markers of polarity and mating. In contrast, broadband noise disrupted actin integrity, while consonants produced no measurable effects. These results suggest that rhythmic continuity and spectral coherence, key features of speech, can modulate cytoskeletal organization in non-auditory cells. By reframing vocal language as mechanical input rather than semantic content, this study bridges microbial cell biology with acoustic ecology and proposes a new lens for exploring how human-generated soundscapes physically influence living systems.

microbiology↗

bioRxiv2021

Pentosan polysulfate inhibits attachment and infection by SARS-CoV-2 in vitro: insights into structural requirements for binding.

Two years since the outbreak of the novel coronavirus SARS-CoV-2 pandemic, there remain few clinically effective drugs to complement vaccines. One is the anticoagulant, heparin, which in 2004 was found able to inhibit invasion of SARS CoV (CoV-1) and which has been employed during the current pandemic to prevent thromboembolic complications and moderate potentially damaging inflammation. Heparin has also been shown experimentally to inhibit SARS-CoV-2 attachment and infection in susceptible cells. At high therapeutic doses however, heparin increases the risk of bleeding and prolonged use can cause heparin-induced thrombocytopenia, a serious side-effect. One alternative, with structural similarities to heparin is the plant-derived, semi-synthetic polysaccharide, pentosan polysulfate (PPS). PPS is an established drug for the oral treatment of interstitial cystitis, is well-tolerated and exhibits weaker anticoagulant effects than heparin. In an established Vero cell model, PPS and its fractions of varying molecular weights, inhibited invasion by SARS-CoV-2. Intact PPS and its size-defined fractions were characterized by molecular weight distribution and chemical structure using NMR spectroscopy and LC-MS, then employed to explore the structural basis of interactions with SARS-CoV-2 spike protein receptor-binding domain (S1 RBD) and the inhibition of Vero cell invasion. PPS was as effective as unfractionated heparin, but more effective at inhibiting cell infection than low molecular weight heparin (on a weight/volume basis). Isothermal titration calorimetry and viral plaque-forming assays demonstrated size-dependent binding to S1 RBD and inhibition of Vero cell invasion, suggesting the potential application of PPS as a novel inhibitor of SARS-CoV-2 infection.

biochemistry↗