The enzyme consists of a single polypeptide chain. The palm region is thought to catalyze the phosphoryl transfer, and the finger region is thought to interact with the incoming nucleoside triphosphate and the template base it is paired to. It is possible that mutations, deletions, or insertions destroyed this activity; E. All residues except Met are conserved in Taq polymerase. Thermophilic organisms have been found to have high GC content. Place Order. Composition: The enzyme consists of a single polypeptide chain.
About Us. This residual contamination may limit the use of cloned Taq in the detection of dilute bacterial DNA in certain samples. Trace contamination may be impossible to completely remove, and indeed certain estimates of contamination counts in commercially available Taq have claimed as many as genome equivalents of bacterial DNA per unit of enzyme.
Several methods for removing bacterial DNA from Taq polymerase have been tested and appear in the literature. Methods such as exposure to ultraviolet light below nm UVB or UVC has the effect of making DNA resistant to amplification; however it also affects the integrity of the Taq polymerase, reducing the efficiency of nucleoside incorporation.
Ultra-filtration of the Taq polymerase, while often able to eliminate false-positives, does so with the unwanted effect of decreasing the assay sensitivity. In addition to the above methods, restriction endonucleases and DNAse I treatment to digest DNA in Taq preparations may introduce contaminants or become the contaminants themselves. A recent methodology under interrogation is the serial dilution of the Taq polymerase up to fold to effectively dilute-out the contaminating bacterial DNA while maintaining Taq activity and sensitivity.
This technique has the consequence of reaction plateauing at lower cycle numbers. This effect generates a lower signal in end-point analysis, with minimal consequence to quantification based on a threshold during the exponential phase. Holland, P. Deoxyribonucleic acid polymerase from the extreme thermophile Thermus aquaticus. Chien, A. Journal of Bacteriology. Longley, M. Nucleic Acid Research 18 24 Maiwald, M. Molecular and Cellular Probes 8 1 Optimizing Taq polymerase concentration for improved signal-to-noise in the broad range detection of low abundance bacteria.
Taq polymerase was first extracted and stabilised from Thermus Aquaticus in by Chien et al, meaning that PCR automation was possible and the process of copying huge amounts of a single targeted piece of DNA could be significantly streamlined. It quickly replaced DNA polymerase from E. It works by moving along the strand of DNA and using it as a template for building a brand new strand which has been marked by a primer into a new, double stranded segment of DNA.
The speed with which this can be done then allows huge amounts of DNA to be replicated, enabling applications such as the mapping done as part of the Human Genome Project, DNA fingerprinting, diagnosis of infectious and inherited diseases and a myriad of other, often life changing and life saving practices.
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