Anion-mediated lysine-arginine interaction. Evidence in Chaetopterus variopedatus sperm protamine.

Chaetopterus ariopedatus sperm protamine is a stable oligomer. Specific amino acid side chain modifications show that the oligomeric structure depends on anion-mediated lysine-arginine interactions. The occurrence of this type of interaction is confirmed by the finding that poly-L-arginine readily forms aggregates with poly-L-lysine or with the native but not with the protamine with carbamylated epsilon-amino groups.