What is Deoxyguanosine Triphosphate (dGTP)?

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What is dGTP?

Deoxyguanosine triphosphate (dGTP) is a nucleotide with a purine base (guanine), deoxyribose sugar, and three phosphate groups. It’s one of the four dNTPs (deoxynucleoside triphosphate) required for DNA synthesis, along with:

Each of the deoxynucleoside triphosphates, including dGTP, forms a phosphodiester bond to form new strands of DNA, using DNA polymerase enzyme and energy.

Besides acting as a building block in DNA replication, dGTP also acts as a metabolite in several biological processes and an essential raw material in molecular biology, biochemistry, and biotechnology laboratories to perform in vitro biochemical reactions, such as PCR.

dGTP is also referred to using the names 2′-deoxyguanosine-5′-triphosphate, 2′-deoxyguanosine triphosphate, and deoxy-GTP. Its molecular formula is C10H16N5O13P3 and has a molecular weight of 507.181 g/mol.

dGTP Synthesis

dGMP acts as a precursor for the synthesis of dGTP. The process occurs via two methods, either by enzymatic synthesis or chemical phosphorylation. 

  • Enzymatic synthesis: In this process, highly specific enzymes are used to carry out the phosphorylation process. There’s no additional purification step in the process and all the impurities (such as pyrophosphates and modified nucleotides) and PCR inhibitors (for example, deoxynucleoside tetraphosphate) are eliminated.
  • Chemical phosphorylation: It’s the process of the addition of phosphate groups to dGMP without utilizing enzymes. It requires an extra purification step after the production of the nucleotide to eliminate impurities and trace compounds like PPi, deoxynucleoside diphosphates, and other ionic compounds, such as acetic acid.

In this article, we will cover the functions of dGTP, how it performs those functions, its structural characteristics, and how it is different from GTP (guanosine triphosphate).

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dGTP vs GTP

dGTP and GTP differ from each other mainly on structural aspects. However, this parameter also separates them on the functional ground. 

Some of the significant differences between dGTP and GTP include:

dGTP

GTP

1. It contains deoxyribose sugar.

It contains ribose sugar.

2. Its molecular formula is C10H16N5O13P3.

Its molecular formula is C10H16N5O14P3.

3. It doesn’t have a hydroxyl group at
its 2’ position of the sugar.

It has a hydroxyl group at
its 2’ position of the sugar.

4. It’s an essential substrate for DNA replication.

It’s an essential component of transcription.

5. It’s involved in the synthesis of DNA.

It’s involved in the synthesis of RNA.

6. Apart from being involved in the
replication process, it acts
as a metabolite in certain biological
processes, including purine metabolism and thioguanine action pathways.

Its functions include energy transfer
in cells (can be readily converted into ATP),
genetic translation, instability in
microtubule dynamics, and translocation of proteins in mitochondria.

7.  Molecular structure of dGTP. Molecular structure of GTP.

How Does dGTP Work?

dGTP contains three phosphate groups, alpha, beta, and gamma phosphates. They are joined together by high-energy phosphoanhydride bonds. 

When in vitro DNA amplification or in vivo DNA synthesis occurs, two phosphate groups are removed for base incorporation in the new strand of nucleic acid.

During DNA synthesis, the two phosphates, alpha, and beta are removed in the reaction, leading to the formation of dGMP (deoxyguanosine monophosphate). The removed PPi groups provide the energy to the DNA polymerase enzyme to add the upcoming nucleotide into the newly synthesized DNA strand.

The 5’ phosphate group of dGMP joins with the 3’ hydroxyl group of the nucleotide of the growing chain. This leads to the formation of a phosphodiester bond between two nucleotides.

What is dGTP Used For? Common Applications

dGTP is a nucleoside triphosphate having extensive roles and uses in organisms and in vitro lab workflows. 

In organisms

  • dGTP acts as a building block for DNA synthesis. 
  • It is one of the competitors against acyclovir for inhibiting the onset of viral replication in the treatment of HSV.
  • It’s also a substrate in the regulation of the synthesis of deoxynucleotides by the enzyme ribonucleotide reductase enzyme.  
  • It acts as a metabolite in several biological processes of the organisms, including Escherichia coli (E.coli), humans, mice, Arabidopsis thaliana, and many others. It includes the azathioprine action pathway, thioguanine action pathway, mercaptopurine action pathway, and purine metabolism. 
  • It acts as an allosteric activator of the enzyme tetrameric SAMHD1 deoxynucleoside triphosphate triphosphohydrolase. dGTP binds at the active site of the enzyme, which leads to some conformation changes and activation of the enzyme.

In molecular biology laboratories

To perform lab experiments, an excellent dGTP is essential, as a poor-quality reagent can ruin entire workflows. Thus, it’s necessary to refer to the documents, such as certificate of analysis, product information sheet, safety data sheet (SDS), and other user guides offered by the seller.

Furthermore, to check the quality of the product, look for the following points:

  • The product has 99% purity, which is confirmed by HPLC (a chromatography technique).
  • It’s free of E.coli or human DNA.
  • The product is highly stable.

A range of pure and modified forms of dGTP are available in the market, which assists in many lab assays, along with other reagents, which include other dNTPs (dATP, dCTP, and dTTP), tris-HCL buffer, primers, DNA polymerase enzyme, EDTA, and other chemical substrates. 

The dGTP solution for the experiment is prepared by dissolving dGTP in a 10 mM-50 mM tris buffer (as guided by the product user manual).

Some of the applications of dGTP are:

  • dGTP is used in several lab assays, including:
  • PCR
  • RT-PCR
  • DNA sequencing
  • DNA labeling 
  • Molecular cloning/synthesis of recombinant DNA
  • Genomic sequencing
  • Microarray
  • qPCR
  • cDNA synthesis
  • Site-directed mutagenesis
  • Long-range PCR
  • Genotyping
  • DHPLC
  • Its analog, 7-Deaza-dGTP, is used in in vitro sequencing techniques to improve the PCR yield when the template DNA is rich in GC content.

dGTP Structure

Deoxyguanosine triphosphate is a nucleoside triphosphate with a guanine base (a purine), three phosphate groups joined by phosphoanhydride bonds, and deoxyribose sugar. The deoxyribose does not contain a hydroxyl group at the 2’ position of the sugar ring. 

The CAS number of dGTP is 2564-35-4. The number is used to provide a unique identification to the chemical and not get it mistaken by any other chemical compounds.

molecular structure of dGTP

Figure: An illustration of the structure of dGTP.

High-Quality Scientific Equipment on Flexible Lease

dGTP is a purine-based nucleotide, having application in DNA synthesis. Furthermore, it acts as a metabolite in several organisms and facilitates certain biological processes, such as purine metabolism.

The compound is also used in labs to perform a spectrum of applications, such as standard PCR, long-range PCR, DNA labeling, and sequencing. All these procedures help scientists understand the metabolic processes of organisms and get better insights into their way of living.

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