Fig. 2: The overall features of a full-length rA3G dimer and the enhanced electrostatic potential at the dimer junction.

a, b Two views of the dimeric rA3G of the E/Q structure, with the two subunits colored in green and light-blue. The dimensions of the dimer are indicated. Inset B a close-up view around the box area in yellow dashed line in b, showing 18 charged/polar and hydrophobic residues from two subunits circling the dimeric junction. Centered around the two R24, the location of these residues is suitable for binding single-stranded nucleic acids through charge interactions with phosphate backbone and hydrophobic stacking with the bases. c, d The surface charge calculated from rA3G dimer as viewed in b (c) or from the light-blue rA3G monomer in b (d). The averaged electrostatic potentials (EP) calculated for the rA3G dimer is + 8.3 kT/e for area centered around the R24 across the dimer junction (in dashed box in c, and Inset c in close-up), whereas the averaged EP for an rA3G monomer is 1.9 kT/e around the same R24 area (in dashed box in d, and Inset d in close-up) (see Methods on electrostatic potentials calculation, and calculated EP values are provided as a Source Data file), which indicates a significant enhancement of the positive EP around R24 area due to dimerization.