Electron micrographs of the HIV-1 virions interacting with different constructs of GRFT-based lectins. (A) Projection of untreated HIV-1 virions. Virions are observed as ~ 100 nm circles in the imaging field which includes 10-nanometer-sized protein-A gold fiducials which appear as dark spots. (B, C) Slices through tomograms of untreated HIV-1 virions with red arrows indicating individual Env proteins. (D) Projection of HIV-1 virions that were incubated with mGRFT prior to vitrification. (E, F) Slices through tomograms of HIV-1 virions treated with mGRFT. Representative Env glycoprotein spikes are indicated by red arrows (E). A patch of glycoprotein spikes is indicated by a red arc (F). (G) Projection of HIV-1 virions that were incubated with native GRFT prior to vitrification. (H, I) Slices through tomograms of virions at the periphery of the aggregates in virions treated with native GRFT. (J–M) Slices through tomograms collected from vitreous preparations of HIV-1 virions with GRFT tandemer constructs, 2mGRFT (J), 2mGRFT3 (K), 3mGRFT (I), and 4mGRFT (M). Scale bars are 500 nm in panels (A, D, and G) and 50 nm in the remaining panels.