Table 2.

E. coli DNA helicases.

S. No.	Name of helicase	Mol. mass (kDa)	Gene	Polarity	Remarks
1.	DnaB protein a	52	dnaB	5′−3′	Replicative helicase. Moves on lagging strand of replication fork.
2.	PriA proein b	81.7	priA	3′−5′	Replicative helicase. Formerly called n′‐protein. Binds to ssDNA at primosome assembly sites.
3.	Rep protein c	72.8	rep	3′−5′	Replicative helicase, unwinds the phage DNA in a highly processive and catalytic manner.
4.	UvrAB	103	uvrA	5′−3′	Repair helicase. Involved in nucleotide excision repair.
	complex d	76	uvrB		UvrB is helicase component
5.	Helicase II (UvrD) e	82	uvrD	3′−5′	Repair helicase. Involved in nucleotide excision repair.
6.	Helicase IV f	78	helD	3′−5′	Originally called as 75 kDa helicase. Helicase activity stimulated by SSB.
7.	RecQ g	80	recQ	3′−5′	Recombination helicase.
8.	RecBCD	13.4	recB	3′−5′	Catalyzes the first step in the recombinational repair of dsDNA breaks.
	complex h	129	recC		Highly processive helicase with bipolar polarity.
	(exo V)	66	recD	5′−3′
9.	RuvAB i	22 37	ruvA ruvB	5′−3′	Recombination helicase. It is an ATP‐driven translocase (pump) that promotes branch migration.
10.	Helicase I j	192	tral	5′−3′	First helicase identified. May be involved in site‐specific nicking reaction.
11.	RecG k	76	recG	3′−5′	A junction‐specific DNA helicase that acts postsynap‐tically to drive branch migration of holliday junction.
12.	Rho l	46	rho	5′−3′	RNA·DNA helicase, can also unwind RNA·RNA but not DNA·DNA.
13.	Helicase III m	20	?	5′−3′	Smallest prokaryotic helicase. SSB protein inhibits the ATPase activity of the protein.
14.	DinG n	?	DinG	5′−3′	DNA damage inducible helicase. It is a monomer in solution.

^a [ 71]; ^b [72]; ^c [1]; ^d [73][74]; ^e [75]; ^f [1]; ^g [43]; ^h [76]; ⁱ [21]; ^j [1]; ^k [77]; ^l [2]; ^m [1]; ⁿ [78].