Journal: Nature chemistry

Article Title: Synthetic O-acetylated sialosides facilitate functional receptor identification for human respiratory viruses.

doi: 10.1038/s41557-021-00655-9

Figure Lengend Snippet: Fig. 4 | Glycan microarray studies reveal binding patterns associated with host specificities. a, Column graphs of viral receptor selectivities. See Supplementary Fig. 9 for the chemical structures of the compounds. Additional results with different concentrations of proteins are presented in Supplementary Fig. 12. Columns show the background-subtracted average relative fluorescence unit (RFU) values of four replicates. Error bars indicate the s.d. of the RFUs. b, Heat-map presentations of viral receptor selectivities. In the heat map, the signal intensities are normalized with the highest value in each protein defined as 1.0 and shown with a colour gradient. Concentrations of Fc-tagged proteins presented are: BCoV S1A 0.3 μg ml–1, OC43 S1A 0.3 μg ml–1, HKU1 S1A 30 μg ml–1, ICV HEF 0.3 μg ml–1, IDV HEF 0.3 μg ml–1, porcine torovirus (PToV) HE 3 μg ml–1, BToV HE 3 μg ml–1, BCoV HE 3 μg ml–1, ECoV HE 3 μg ml–1, RbCoV HE 3 μg ml–1, CRCoV HE 3 μg ml–1, MHV-S HE 3 μg ml–1, ECoV S1A 3 μg ml–1, RbCoV S1A 3 μg ml–1 and CRCoV S1A 10 μg ml–1. Representative surface dissociation constants (Kd,surf) were obtained for the binding of HKU1 S1A with compounds 3g (9-O-Ac, 60 nM) and 3d (7,9-di-O-Ac, 85 nM). See supplementary Fig. 13 for binding curves. Sialoforms 1b and 2b (4,7-di-O-Ac Neu5Ac) were not included in the library because they have not been documented to be naturally occurring.

Article Snippet: The biotinylated compounds were printed on streptavidin-coated glass slides (SuperStreptavidin Microarray Substrate Slides, ArrayIt Inc) using a Scienion sciFLEXARRAYER S3 non-contact microarray equipped with a Scienion PDC80 nozzle (Scienion Inc).

Techniques: Glycoproteomics, Microarray, Binding Assay, Fluorescence

Journal: Microbiology Spectrum

Article Title: Nanobody engineering for SARS-CoV-2 neutralization and detection

doi: 10.1128/spectrum.04199-22

Figure Lengend Snippet: Relative binding strengths of trimeric nanobodies to RBD and Spike S1 domain variants on an antigen microarray. ( A ) Three multimodular nanobody constructs were tested for binding to RBD variants with amino acid changes K417N, E484K, or N501Y, and to spike the S1 domain with four amino acid changes (K417N, E484K, N501Y, and D614G). Fluorescence signals of Dylight 633-labeled multimodular nanobodies Tri-Ty1, Tri-TMH, and Tri-TMV bound to the different RBD and S1 variants are shown normalized relative to the signal from binding to wild-type RBD or S1 for each nanobody, respectively. Error bars represent the standard deviation of two replicate measurements. ( B ) Location of the amino acid changes within the SARS-CoV-2 RBD. Amino acid change N501Y is found in the Alpha and Beta variants ( , ), and the Beta variant displays the additional changes K417N and E484K . Delta variant carries none of the three tested RBD amino acid changes, while Omicron displays N501Y, K417N, and an alternative change at residue 484, E484A.

Article Snippet: Wild-type and variant SARS-CoV-2 RBD and spike S1 domains were biotinylated and arrayed as duplicate spots (0.1 ng per spot) in the wells of streptavidin-coated microtitration plates using a piezoelectric non-contact microarray dispenser (Nano-Plotter, GeSiM, Germany).

Techniques: Binding Assay, Microarray, Construct, Fluorescence, Labeling, Standard Deviation, Variant Assay, Residue