sa biosensor  (Sino Biological)

Journal: bioRxiv

Article Title: Expanding the chemical diversity of RNA by transcriptional incorporation of amino acid- and glycosyl-modified nucleotides

doi: 10.64898/2026.04.22.720138

Figure Lengend Snippet: A) Nucleotide composition across the 40-nt random region of the starting SELEX library (round 0) and after selection round 6. Grey shades indicate nucleotide identities as shown in the legend. B) NGS profiling showing sequence enrichment (frequency, %) of the top 10 candidates across SELEX rounds 2–6. C) Screening of selected sequences for binding to H1 hemagglutinin using BLI. Average BLI response after 98 s of association for sequences H1-1 and H1-3 containing histidine-modified uridines, immobilized on streptavidin BLI sensors and exposed to H1 hemagglutinin in solution at 150 nM (n = 3). D) Binding kinetics of aptamer H1-His-1 to H1 hemagglutinin measured by BLI. The biotinylated aptamer was immobilized on streptavidin-coated BLI sensors and exposed to a two-fold dilution of H1 hemagglutinin in solution starting at 150 nM. Association phase: 0–400 s; dissociation phase: 400–1600 s. Global fitting of association and dissociation curves (red lines) was performed using Evilfit accounting for surface effects. Residuals are shown below. E) Assessment of H1-1 aptamer specificity. Average BLI response after 98 s of association for sequence H1-1 containing histidine-modified uridines, immobilized on streptavidin BLI sensors and exposed to 150 nM H1 hemagglutinin and H5 hemagglutinin or a 300 nM nanobody control in solution (n = 3). F) Evaluation of the impact of uridine modifications on H1-1 aptamer binding. Average BLI response after 98 s of association for H1-1 containing histidine-modified uridines or substituted with leucine- or 2F’- modified uridines, immobilized on streptavidin BLI sensors and exposed to 150 nM H1 hemagglutinin in solution (n = 3).

Article Snippet: Refolded, biotinylated RNA aptamer were immobilized on Octet® Streptavidin (SA) Biosensors (Sartorius).

Techniques: Selection, Sequencing, Binding Assay, Modification, Control

Journal: bioRxiv

Article Title: Localization-dependent activation of the DEAD-box ATPase Vasa by eLOTUS domains

doi: 10.64898/2026.03.28.715021

Figure Lengend Snippet: (A) Scheme of Vasa core - Tejas-eLOTUS WT and I-MUT fusion proteins (left). Mutations in the Vasa - eLOTUS interface (I-MUT) are indicated. Biolayer interferometry analysis (right) of the fusion proteins was performed in the presence of 2 mM ATP and an ATP-regenerating system. Streptavidin biosensors were loaded in the presence of 5 nM biotinylated R13 ssRNA oligo. For reference, thick lines indicate 20 µM protein concentration. (B) MD-generated structural model of the complex composed of the Vasa-CTD, the Tejas-eLOTUS domain and a short ssRNA oligo. The frame shown corresponds to 6.125 ns. Charged residues in the unstructured C-terminal tail of the eLOTUS domain are highlighted in ball-and-stick representation. (C) Multiple sequence alignment of the C-terminus of the eLOTUS domains from various animals with the positively charged residues in the very C-terminus highlighted in blue. (D) GST pull-down assay using 1 nmol GST, GST-Tejas-eLOTUS WT, C-MUT (K94A/K96A/R98A), or C-DEL (Δ94-100) and 2 nmol His-Vasa 200-661*. Molecular weight marker (in kDa) is indicated at the left. Input and pull-down samples originated from one experiment but were loaded onto two gels. Lanes with irrelevant data were removed. His-Vasa 200-661* contains a short GS linker at its C-terminus not affecting Vasa function. (E) dsRNA unwinding assay in the presence of 3 mM ATP and an ATP-regenerating system, 5 nM labeled dsR13 oligo, and 500 nM unlabeled competitor R13 ssRNA oligo using 7.5 µM of the His-Vasa 200-661* and 100 µM GST or wildtype or mutant GST-Tejas-eLOTUS domain. All samples originated from one experiment but were loaded onto two gels. Lanes with irrelevant mutants were removed. The use of similar amounts of the eLOTUS domain variants was verified by PAGE ( Supplementary Figure 6D ). His-Vasa 200-661* contains a short GS linker at its C-terminus not affecting Vasa function. (F) ATPase assay using 1 µM of His-Vasa 200-661*, 10 µM R26 ssRNA oligo, 8 nM [ψ- 32 P] ATP, in the presence of buffer, 100 µM wildtype or mutant His-Tejas-eLOTUS domains. All samples originated from one experiment but were loaded onto two thin layer plates. The use of similar amounts of the eLOTUS domain variants was verified by PAGE ( Supplementary Figure 6D ). His-Vasa 200-661* contains a short GS linker at its C-terminus not affecting Vasa function. (G) Biolayer interferometry analysis of Vasa-eLOTUS fusion proteins as indicated in the presence of 2 mM ATP and an ATP-regenerating system. Streptavidin biosensors were loaded in the presence of 5 nM biotinylated R13 ssRNA. Association and dissociation curves obtained with 20 µM protein are shown. Full titration series and quantification are provided in Supplementary Figure 6E .

Article Snippet: For biolayer interferometry (BLI) analysis, Octet ® SA (Streptavidin) Biosensors (Sartorius) were pre-incubated for at least 10 minutes in reaction buffer containing 20 mM Tris (pH 7.5), 150 mM NaCl, 5 mM MgCl 2 , 5 mM DTT, 2 mM ATP, 20 mM creatine phosphate (Roche), 80 ng/mL creatine kinase (Roche), 0.02% Tween 20 (Roth), and 50 ng/μL heparin (sodium salt from porcine intestinal mucosa, Sigma-Aldrich).

Techniques: Protein Concentration, Generated, Sequencing, Pull Down Assay, Molecular Weight, Marker, Labeling, Mutagenesis, ATPase Assay, Titration