DHLA-EG11-DiMan and DHLA-EG3-OH were synthesized in house our previously established protocols. Preparation of QD-DiMan. QD (53.3 µM in toluene, 22.5 µL, 1.2 nmol) was precipitated by adding EtOH (1.2 ml) and centrifuged at 15000×g for 10 mins. The supernatant was discarded and the pellet was dissolved in CHCl3. DHLA-EG11-DiMan (2.5 mg, 1.8 µmol;) in CHCl3, NaOH (0.1 M in EtOH, 2.2 µmol) and MeOH were then added and the reaction mixture was covered by foil and stirred at r.t. for 30 mins. Hexane was added till the solution became cloudy and the suspension was centrifuged at 15000×g for 3 mins. The pellet was then dissolved in H2O and was washed 3 times with H2O using a 30 kDa MWCO spin filter at 15000×g for 2 mins. All supernatants and washes were collected and stored for sulfur-phenol quantification of the surface coverage. This yielded QD-DiMan with a hydrodynamic dimeter (𝐷 ℎ ) of 12.37 ± 0.05 nm and a full width at half maximum (FWHM) of 6.00 ± 0.05 nm as measured by dynamic light scattering. Thermodynamic studies. All FRET studies were performed using a Cary Eclipse Fluorescence Spectro-photometer and a SUPRASIL® quartz cuvette. All data were analyzed using Microsoft Excel 2016 and graphs were plotted using Origin 2019b software. Samples were excited with λex = 450 nm and the fluorescence spectra were collected from 480 to 750 nm, with intervals (Δλ) of 1 nm. Excitation and emission slit widths and PMT were adjusted to optimize the fluorescence signal. FRET assays were performed by adding protein to QD-DiMan (in binding buffer, 20 mM HEPES, 100 mM NaCl, 10 mM CaCl2, pH 7.8, containing 0.1 mg/mL of BSA to minimize non-specific interactions and also adsorption onto surfaces). All fluorescence spectra were corrected for background of the same concentration lectin only under identical conditions. Temperatures were controlled by a water bath and dry bath for the buffers and samples, respectively. The cuvette temperature was maintained by a built in temperature control unit where temperature was maintained using a water pump system. Kinetic studies. Kinetic experiments were performed using a TgK scientific SFA-20 Rapid Kinetics stopped-flow accessory in conjunction with a Cary Eclipse Fluorescence Spectrophotometer. Measurements were taken using λex = 450 nm, and alternating the measurement between the fluorescence intensity at λem = 550 nm and 628 nm over time, with a time resolution of 0.0125 s. The apparatus consists of two syringes (A and B) fed to a 80 µL high grade Spectrasil B cuvette via capillary tubes, which then continue to a switch triggered when 0.3 mL of sample is injected. Before measurement, the system was pre-flushed with H2O (40 mL), followed by BSA (1 mg/ml in binding buffer, 2 mL) in syringe A and binding buffer (2 mL) in syringe B and finally both syringes with binding buffer (10 mL). All kinetics measurements were performed in binding buffer containing 5 g/mL of His6-Cys. We have found previously that addition of His6-Cys can enhance the fluorescence and reduce nonspecific interactions for the QD. Association measurement were obtained by loading syringe A with 2.5 mL of the QD, and syringe B with 2.5 mL of protein, both at a final concentration of 40 nM. Dissociation measurements were obtained by loading syringe A with premixed Protein and QD, both at a final concentration of 40 nM and syringe B with 2.5 mL of D-mannose (40 mM). Backgrounds were obtained by loading syringe A with binding buffer, and syringe B with the protein only (40 nM). For each run, the system was flushed with sample (1.5 mL per syringe) before starting measurements. Each measurement was ran for 60 s before the next injection, where buffer was used to displace the sample once the sample had been completely injected, until the fluorescence signal was observed to drop. Background time profiles were obtained in the same way. Corrected fluorescence profiles were obtained for both association and dissociation experiments by subtracting the background time profiles at corresponding injection volumes and averaging 3 measurements at each λem with consistent fluorescence plateau values. FRET ratio-time profiles were obtained by the ratio of the averaged corrected fluorescence profile at λem = 628 nm and that at λem = 550 nm, over time. The kinetic profiles for DC-SIGNR at a 1:1 PQR showed low signal to noise due to weak binding interaction. Therefore, to improve this, the data was smoothed by averaging every five time points, providing a time resolution of 0.0625 s.