Table 1.  .

Characteristics of catalytically active prokaryotic and eukaryotic Argonaute proteins

Host	Argonaute, protein ID	Guide, lengthа	5' end of the guideb	Target	Reaction temperatureс	Ion	Mismatches in a duplexd	Catalytic activity	References
Prokaryotic Argonaute proteins
Aquifex aeolicus	AaAgo, WP_010880937.1	DNA 18‒24	5′-P; ?	RNA, (DNA ?)	opt. 55°C; up to 75°C	Mg2+, Mn2+	?	Guide-dependent	[113–115]
Clostridium butyricum (strains TK520, CWBI 1009)	CbAgo, WP_058142162.1; CbcAgo, WP_045143632.1	DNAe (RNA weakly) 16‒18	5′-P; none	DNA* (RNA weakly)	opt. 37°C; 30‒60°C (CbcAgo opt. 37‒42°C; 25‒55°C)	Mg2+, Mn2+, Co2+	↓5, 6, 12‒15 nt	Guide-dependent; guide-independent	[116, 121–123]
Clostridium perfringens	CpAgo, WP_003477422.1	DNA 15‒30 (≥12)	5′-P; none	DNA (RNA)	opt. 37°C; 4–70°C	Mg2+, Mn2+	↓12‒15 nt	Guide-dependent	[124]
Ferroglobus placidus	FpAgo, WP_012966655.1	DNA 15‒16	5′-P; G1	DNA	75–99°C	Mg2+, Mn2+, Co2+, Ni2+	↑7 nt; ↓3,8,11‒15 nt	Guide-dependent	[125]
Intestinibacter bartlettii	IbAgo, WP_007287731.1	DNA 15‒30 (≥14)	5′-P; none	DNA	opt. 37°C; 4–60°C	Mg2+, Mn2+	↓14‒16 nt	Guide-dependent	[124]
Kurthia massiliensis	KmAgo, WP_010289662.1	DNA (RNA) 16‒20 (≥12)	5′-P; none	DNA (RNA)	opt. 37‒60°С; from 25°С	Mn2+, Mg2+, weakly Co2+	↓4, 5, 10‒15 nt (DNA‒DNA); ↓4, 8‒11 nt (DNA‒RNA); ↓3‒11 nt (RNA‒DNA)	Guide-dependent; guide-independent (37°С)	[126, 127]
Limnothrix rosea	LrAgo, WP_075892274.1	DNAe 16‒18 (≥10)	5′-P; none	DNA	opt. 37°C; 30–54°C	Mn2+, Mg2+, weakly Co2+	↑4‒8 nt; ↓10‒15 nt	Guide-dependent; guide-independent	[122]
Methanocaldococcus fervens	MfAgo, WP_015791216.1	DNA, RNA 16	5′-P DNA and RNA; 5′-OH DNA	DNA	opt. 80‒90°C; from 54°C	Mn2+, Mg2+, Co2+	?	Guide-dependent	[128]
Marinitoga piezophila	MpAgo, WP_014295921.1	RNA 16‒40	5′-OH; none	DNA (RNA)	37, 55, 60°C	Mn2+, Mg2+, weakly Ni2+	↓5, 7, 8 nt; ↓5‒15 nt dinucleotide mismatches	Guide-dependent	[129–131]
Methanocaldococcus jannaschii	MjAgo, WP_010870838.1	DNA 15‒41	5′-P; purines	DNA	opt. 75‒95°C; from 37°C	Mg2+	? ↓10‒11 dinucleotide mismatches	Guide-dependent; guide-independent	[101, 132, 133]
Natronobacterium gregoryi	NgAgo, WP_005580376.1	DNA 22‒24	5′-P; ?	DNA ? (RNA ?)	37°C	Mg2+	?	Guide-dependent	[134–138]
Pyrococcus furiosus	PfAgo, WP_011011654.1	DNA 15‒31	5′-P; none	DNA	opt. 87‒99.9°C; from 37°C	Mn2+, Co2+	?	Guide-dependent; guide-independent	[139–141]
Synechococcus elongatus	SeAgo, WP_011244830.1	DNAe 14‒24	5′-P; none	DNAe	opt. 37°C	Mn2+, weakly Mg2+	↑5, 6, 10 nt; ↓7, 12‒15, 18 nt	Guide-dependent; guide-independent	[142]
Thermotoga profunda	TpAgo, WP_041081268.1	RNA 21	5′-OH; ?	DNA	60°C	Mg2+, Mn2+	?	Guide-dependent	[130]
Thermus thermophilus	TtAgo, WP_011174533.1	DNAe 13‒25	5′-P; C1 G1'	DNAe (RNA)	opt. 73‒75°C; ⩾20 °C ssDNA; ⩾ 65°C plasmids	Mn2+, Mg2+	↓12‒15 nt	Guide-dependent; guide-independent	[100, 106, 143–149]
Eukaryotic Argonaute proteins
Homo sapiens	hAgo2, NP_036286.2	RNAe (DNA) 20‒21	5′-P; U1 A1'	RNAe	37°C	Mg2+	↓2‒8 nt (target binding); ↓8‒11 triple mismatch	Guide-dependent	[99, 139, 150–152]
Kluyveromyces polysporus (Vanderwaltozyma polyspora)	KpAgo, XP_001644461.1	RNAe (DNA) 12‒17 (11‒25)	5′-P; U1	RNAe	25‒30°C	Mg2	↓7‒14 nt (↓↓9‒13 nt)	Guide-dependent	[102, 153]
Bombyx mori	SIWI, NP_001098066.2	RNAe 28‒30	5′-P; U1	RNAe	26, 37°C	Mg2+, Mn2+	↓2‒7 nt (target binding)	Guide-dependent	[103, 154, 155]

^aThe type of guide nucleic acid and its length (number of nucleotides). ^bCharacteristics of the 5'-end of the guide: P—phosphate group, OH—hydroxyl group; the presence of specificity to the nitrogenous base is indicated: none—no specificity, A/U/G/C—   types of nitrogenous bases, 1—the first nucleotide of the guide chain; 1'—the first nucleotide of the target chain. Here and further: ?—unknown. ^cThe temperature at which Argonaute protein could cleave target; opt.—the temperature optimum, the temperature range at which the Argonaute cleaves targets is also given. Discrete    temperature values are given for publications where measurements were carried out only under these conditions. ^dThe effect of mismatches (unpaired nucleotides of the duplex guide–target) on the efficiency of target cleavage; the positions of the nucleotides (nt) are numbered relative to the 5'-end of the    guide. ↑—increase in cleavage efficiency, ↓—decrease in cleavage efficiency. ^eBoth in vitro and in vivo.