Table 2.

Transformation efficiency of assembled PCR fragments generated either by Taq DNA polymerase or PfuC_x DNA polymerase

Number of PCR fragments assembled (fragment size in bp)	Number of white colonies (recombinants)a c.f.u./50 ng vector		Percentage of recombinant coloniesb (%)		Assembly efficiencyc (%)
	Taq DNA polymerase	PfuCx DNA polymerase	Taq DNA polymerase	PfuCx DNA polymerase	Taq DNA polymerase	PfuCx DNA polymerase
One (926)	1.12 × 104	1.52 × 105	98	99	9.7	11.0
Two (142,792)	0.44 × 104	0.85 × 105	91	98	3.8	6.2
Two (461, 474)	0.73 × 104	0.86 × 105	96	98	6.3	6.2
Three (142, 327,474)	0.26 × 104	0.36 × 105	84	95	2.3	2.6

^aBlue–white selection was performed to distinguish the recombinant colonies (white) from the colonies carrying vector background (blue).

^bPercentage of recombinants was determined by dividing the number of white colonies by the total number of transformants.

^cAssembly efficiency shows what fraction of transformants is recovered from each assembly reaction compared to the total cell competency. Cell competency of ER2267competent cells used for transformation of Taq-generated PCR fragments was 1.15 × 10⁵ c.f.u. per 50 ng of uncut vector pNEB206A. Cell competency of NEB5-α competent cells used for transformation of PfuC_x-generated PCR fragments was 1.38 × 10⁶ c.f.u. per 50 ng of uncut vector pNEB206A.