A Fusion of Taq DNA Polymerase with the CL7 Protein from Remarkably Improves DNA Amplification.

DNA polymerases are important enzymes that synthesize DNA molecules and therefore are critical to various scientific fields as essential components of in vitro DNA synthesis reactions, including PCR. Modern diagnostics, molecular biology, and genetic engineering require DNA polymerases with improved performance. This study aimed to obtain and characterize a new - fusion DNA polymerase, in which the DNA coding sequence of DNA polymerase was fused with that of , a variant of (Colicin E7 DNase) from . The resulting novel recombinant open reading frame was cloned and expressed in . The recombinant - protein exhibited excellent thermostability, extension rate, sensitivity, and resistance to PCR inhibitors. Our results showed that the sensitivity of - DNA polymerase was 100-fold higher than that of wild-type , which required a template concentration of at least 1.8 × 10 nM. Moreover, the extension rate of - was 4 kb/min, which remarkably exceeded the rate of DNA polymerase (2 kb/min). Furthermore, the fusion protein showed increased resistance to inhibitors of DNA amplification, including lactoferrin, heparin, and blood. Single-cope human genomic targets were readily available from whole blood, and pretreatment to purify the template DNA was not required. Thus, this is a novel enzyme that improved the properties of DNA polymerase, and thus may have wide application in molecular biology and diagnostics.