Terminase, the DNA packaging enzyme of bacteriophage lambda, is a heteromultimer composed of subunits Nu1 and A. The smaller Nu1 terminase subunit has a low-affinity ATPase stimulated by non-specific DNA [1].

1: A mutation correcting the DNA interaction defects of a mutant phage lambda terminase, gpNu1 K35A terminase. Hwang Y, Feiss M; Virology 1999;265:196-205. PMID:10600592