Table 1.

Functional properties of analyzed pAgo proteins in comparison with eAgos

Host	Argonaute	Guide	5′-end; nucleotide preference	Target	Catalytic activity	Functional activity	References
Aquifex aeolicus	AaAgo	DNA	5′-P; Unknown	(RNA; DNA not tested)	Guide-dependent	–	18– 20
Archaeoglobus fulgidus	AfAgo (short pAgo)	DNA (RNA)	5′-P; Unknown	DNA (RNA)	Inactive	–	14– 17
Marinitoga piezophila Thermotoga profunda	MpAgo TpAgo	RNA	5′-OH; None	DNA (RNA)	Guide-dependent	–	36, 37
Methanocaldococcus jannaschii	MjAgo	DNA	5′-P; Purines	DNA	Guide-dependent; Chopping	Reduced plasmid content and transformation efficiency	21– 23
Pyrococcus furiosus	PfAgo	DNA	5′-P; None	DNA	Guide-dependent; Guide-independent	Reduced transformation efficiency	24– 26
Rhodobacter sphaeroides	RsAgo	RNAa	5′-P; g1U	DNAa	Inactive	Reduced transcription of reporter genes and plasmid content	34, 35
Thermus thermophilus	TtAgo	DNAa	5′-P; g1C/t1′G	DNAa (RNA)	Guide-dependent; Chopping	Reduced plasmid content and transformation efficiency; changes in gene expression	27– 33
Homo sapiens	hAgo1	RNA	5′-P; g1U or g1A	RNA	Inactive	miRNA pathway	39
	hAgo2	RNA	5′-P; g1U/t1′A	RNA	Guide-dependent	miRNA pathway	38, 40– 42
Kluyveromyces polysporus	KpAgo	RNA	5′-P; g1U	RNA	Guide-dependent	miRNA pathway	38
Bombyx mori	SIWI	RNA	5′-P; g1U	RNA	Guide-dependent	piRNA pathway	44

^aBoth in vitro and in vivo