So this is Guana dinean, it's small, very polar, and about the volume of two water molecules once you've included all the hydrogen bonding. It's cationic, that's it, there's a single positive charge and is one of the more invasive motif seen in biochemistry. For instance, it's isoelectronic, albeit not, isoatomic, with another powerful denatured urea, which is the main mechanism by which you excrete nitrogenous compounds in metabolism. It also forms the site chain of one of the three cationic amino acids, arginine. The motif is seen here in the protein HIP protease, and it stacked up against another cationic arginine. Now you'd have thought what would these be in cationic residues, you know, that it would be very difficult to have or a rare to have two positively charged groups next to each other, but it's actually a surprisingly common motif in protein structures. Further, the Guana dinean motif is found, albeit in the neutral form, in the base pair guani, where two of its hydrogen bonding structures helped stabilize the core of the double helix of DNA.