Charge radius the composite particle must be modeled as a sphere of negative rather than positive electric charge for the interpretation of electron scattering experiments. In these cases, the square of the charge radius of the particle is defined to be negative, with the same absolute value with units of length squared equal to the positive squared charge radius that it would have had if it was identical in all other respects but each quark in the particle had the opposite electric charge (with the charge radius itself having a value that is an imaginary number with units of length). It is
Ribonucleoprotein particle Ribonucleoprotein particle A ribonucleoprotein particle or RNP is a complex formed between RNA and RNA-binding proteins (RBPs). The term RNP foci can also be used to denote intracellular compartments involved in processing of RNA transcripts. RBPs interact with RNA through binding motifs. Aromatic amino acid residues in this RNA binding motif result in stacking interactions with RNA. Lysine residues in the helical portion of RNA binding proteins help to stabilize interactions with nucleic acids. This nucleic acid binding is a result of the force of attraction between the positive electrical charge of lysine side chains and the negative electrical charge