Bulk production of the antiviral lectin griffithsin

Fuqua, Joshua L.; Hamorsky, Krystal; Khalsa, Guruatma; Matoba, Nobuyuki; Palmer, Kenneth E.

To further validate the gp120 binding activity of GRFT, surface plasmon resonance (SPR) was employed to determine the equilibrium dissociation constant (K d ) (Figure 2c ). The average K d of GRFT to gp120 was found to be 31.9 nM and after 3 months, while GRFT stored at 4°C and room temperature (RT) had K d values of 32.2 and 33.0 nM, respectively. Thus, there is no significant loss in GRFT binding to gp120 after 3 months of storage. Another parameter to highlight is the thermostability of GRFT. Differential scanning fluorimetry (DSF) was used to determine the melting temperature (T m ) of GRFT (Figure 2d) . After 3 months of storage at 4°C or RT, there was no significant change in the T m therefore confirming the structural integrity of GRFT. Lastly, although not discussed here, the concentration of GRFT as determined by OD 280 and the purity of the monomer species monitored by reducing SDS-PAGE were unaltered after 3 months of storage.