What is the Structural Difference Between ATP and dATP

The main structural difference between ATP and dATP is that ATP is a ribonucleotide whereas dATP is a deoxyribonucleotide. That means; the sugar group of the ATP is ribose, which contains a hydroxyl (-OH) group in the 2′ position, while the sugar group of dATP is deoxyribose, which does not contain such hydroxyl group in the 2′ position. Consequently, ATP serves as the energy currency of the cell while dATP serves as one of the four nucleotide precursors for DNA synthesis. 

ATP and dATP are two types of adenine nucleotides found in the cell. Both consist of an adenine base and three phosphate groups attached to the pentose sugar. 

Key Areas Covered 

1. What is the Structure of ATP
     – Definition, Structure, Role in the Cell
2. What is the Structure of dATP
     – Definition, Structure, Role in the Cell
3. What are the Structural Similarities Between ATP and dATP
     – Outline of Common Features
4. What is the Structural Difference Between ATP and dATP
     – Comparison of Key Differences

Key Terms 

ATP (adenosine triphosphate), dATP (deoxyadenosine triphosphate), Deoxyribose, 2′ OH, Ribose 

What is the Structure of ATP 

ATP (adenosine triphosphate) is a ribonucleotide, which serves as the energy currency of the cell. Structure-wise, the nitrogenous base, phosphate groups, and a pentose sugar are the three components of a nucleotide. In ATP, adenine is the nitrogenous base, which attaches to the 1′ position of the pentose sugar. Moreover, ATP contains three phosphoryl groups attached to the 5′ position of the pentose sugar. 

Figure 1: ATP Structure 

The first phosphate group at the pentose sugar is the alpha phosphate group; the second is the beta while the third or the terminal phosphate group is the gamma. Here, the beta and the gamma phosphate groups are high energy phosphate groups. 

What is the Structure of dATP 

dATP (deoxyadenosine triphosphate) is a deoxyribonucleotide, which serves as a precursor for DNA synthesis. Same as ATP, the three structural components of dATP are the adenine base, phosphate groups, and the pentose sugar. Here also, the adenine base attaches to the 1′ position of the pentose sugar. But, the pentose sugar in the dATP is deoxyribose. It does not consist of a 2’hydroxyl group. Only the 3′ position contains a hydroxyl group, which also occurs in the ribose sugar.

Figure 2: dATP Structure

The three phosphate groups, alpha, beta, and gamma also attach to the 5′ position of the deoxyribose sugar.  

Structural Similarities Between ATP and dATP 

• ATP and dATP are two types of adenine nucleotides. 
• They consist of an adenine base and three phosphate groups attached to the pentose sugar. 

Structural Difference Between ATP and dATP 

Definition 

ATP refers to the phosphorylated nucleotide that composes adenosine and three phosphate groups and supplies energy for many biochemical, cellular process, especially to ADP, by undergoing enzymatic hydrolysis. In contrast, dATP refers to one of the two purine nucleotides that are used to synthesize DNA. 

Pentose Sugar 

ATP consists of a ribose sugar while dATP consists of a deoxyribose sugar. And, this causes the main structural difference between ATP and dATP.

2′ Position 

The 2′ position of the ribose of ATP consists of a hydroxyl group while the 2′ position of deoxyribose of dATP consists of a hydrogen. Hence, this is also an important structural difference between ATP and dATP.

Type  

ATP is a ribonucleotide while dATP is a deoxyribonucleotide. 

Role in the Cell 

ATP serves as the energy currency of the cell while dATP serves as a precursor for DNA synthesis. 

Conclusion 

ATP is a ribonucleotide whose pentose sugar is a ribose. Therefore, it consists of a 2′ hydroxyl group in the pentose sugar. On the other hand, dATP is a deoxyribonucleotide whose pentose sugar is a deoxyribose, which does not consist of a 2′ hydroxyl group. Hence, the main structural difference between ATP and dATP is the presence of a 2′ hydroxyl group in the pentose sugar.

Reference:

1. “Adenosine Triphosphate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available Here
2. “2′-Deoxyadenosine Triphosphate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available Here

Image Courtesy:

1. “ATP chemical structure” (CC BY-SA 3.0) via Commons Wikimedia     
2. “DATP chemical structure” (Public Domain) via Commons Wikimedia