What is the Difference Between Base Sequence and Amino Acid Sequence

The main difference between base sequence and amino acid sequence is that a base sequence builds up either DNA or RNA molecule whereas amino acid sequence builds up a protein. Furthermore, base sequence represents a codon sequence that determines an amino acid sequence of a functional protein according to the central dogma of molecular biology.  

In brief, the base sequence and amino acid sequence are two sequences of monomer units, which ultimately build two of the three main macromolecules of the body: the nucleic acids and proteins, respectively. Generally, both types of macromolecules play a key role in storing genetic information and utilizing them in protein synthesis. 

Key Areas Covered 

1. What is a Base Sequence
     – Definition, Macromolecular Formation, Importance
2. What is an Amino Acid Sequence
     – Definition, Macromolecular Formation, Importance
3. What are the Similarities Between Base Sequence and Amino Acid Sequence
     – Outline of Common Features
4. What is the Difference Between Base Sequence and Amino Acid Sequence
     – Comparison of Key Differences

Key Terms 

Amino Acid Sequence, Base Sequence, Nucleic Acids, Protein, Protein Synthesis

What is a Base Sequence 

The base sequence is a series of nucleotide bases of either a DNA or RNA molecule. In general, DNA nucleotides occur in DNA, while RNA nucleotides occur in RNA.  

Structure  

Both DNA and RNA nucleotides differ from each other by the nitrogenous base and pentose sugar present in their structure. Nitrogenous bases occur in two types: purines and pyrimidines. Purine bases include adenine and guanine while pyrimidine bases include cytosine, thymine, and uracil.

Figure 1: DNA and RNA Structure

The four types of nitrogenous bases in the DNA are the adenine, guanine, cytosine, and thymine. But, in RNA, uracil occurs instead of thymine. Also, in DNA, the pentose sugar is deoxyribose, while ribose is the pentose sugar in RNA. However, phosphodiester bonds occur between nucleotides in both DNA and RNA. Besides these, each base sequence has a directionality; one end is the 3′ end, containing a free OH group while the other end is the 5’end with a free phosphate group.

Figure 2: Codon Sequence in RNA

Both DNA and RNA occur in nature either in their primary, secondary, tertiary or Quaternary structure. However, the RNA is typically a single-stranded molecule, but the DNA is usually a double-stranded molecule. Also, the two strands of DNA contain complementary bases to each other. And, the arrangement of these strands appears in an antiparallel manner. 

Function 

The main biological significance of a base sequence is that it represents a codon sequence, which can be used to produce an amino acid sequence of a functional protein in the body. Here, each codon represents an amino acid according to the genetic code.

Figure 3: Genetic Code

Based on the central dogma of molecular biology, the base sequence or codon sequence is transcribed during transcription, producing an mRNA molecule that contains the exact codon sequence. Then, decoding of the mRNA molecule results in the amino acid sequence in a process called translation, with the help of ribosomes.  

What is an Amino Acid Sequence 

An amino acid sequence is a series of amino acids linked together by peptide bonds. The type of amino acids in the sequence is determined by the codon sequence in the mRNA molecule. Therefore, translation is the process that synthesizes the amino acid sequence. Furthermore, it occurs in the cytoplasm of all living cells with the assistance of ribosomes. 

Figure 4: Translation

Structure 

An amino acid sequence serves as the primary structure of a functional protein. The primary structure can further produce the secondary, tertiary, and Quaternary structures. Generally, many proteins have several protein domains, and each domain is a resultant of a single amino acid sequence. Also, each domain performs a unique function related to the core function of the main protein molecule.

Figure 5: Protein Structure

Function 

Proteins are one of the three types of macromolecules in the body. They play a vital role as structural, regulatory, signaling, and ligand-binding molecules. Also, proteins serve as enzymes that catalyze biochemical reactions vital in the metabolism. Furthermore, proteins, like actin and myosin, play structural and mechanical functions in the cytoskeleton. Besides these, other proteins take part in cell signaling, cell cycle, immune response, and cell adhesion.

Moreover, animal intake proteins through their diet. And, their digestion results in releasing both essential and nonessential amino acids, which can be used in protein synthesis.  

Similarities Between Base Sequence and Amino Acid Sequence  

• Base  sequence and amino acid sequence are two types of sequences of  monomers.  
• Each monomer unit covalently binds to the adjacent monomer units.  
• Also, they are generally linear strands, representing the primary structures. However, they can also form secondary, tertiary, and quaternary structures.       
• They are responsible for the formation of two main types of macromolecules found in the animal body.  
• Moreover, these macromolecules are important for the synthesis of proteins. 

Difference Between Base Sequence and Amino Acid Sequence 

Definition 

Base sequence refers to a particular order of nucleotide bases in a DNA or RNA molecule, while amino acid sequence refers to the arrangement of amino acids in a protein. 

Type of Macromolecular Formation 

Moreover, base sequence is responsible for the formation of either DNA or RNA, while the amino acid sequence is responsible for the formation of the primary structure of a protein. 

Type of Bond Formation 

Phosphodiester bonds form between two monomer units of the base sequence, while peptide bonds form between two monomer units of an amino acid sequence. 

Function 

The base sequence is responsible for storing genetic information and revealing them for protein synthesis, while the amino acid sequence is responsible for the production of structural or regulatory macromolecules. 

Conclusion 

A base sequence is a nucleotide sequence of either DNA or an RNA. Here, each nucleotide forms a phosphodiester bond with the adjacent nucleotide. Also, DNA and RNA are responsible for storing genetic information, and this information is important in protein synthesis. In contrast, the amino acid sequence is the sequence of amino acids in the primary structure of a functional protein. However, in between amino acids, peptide bonds occur. Therefore, the main difference between base sequence and amino acid sequence is their structure and functional importance. 

References:

1. Berg JM, Tymoczko JL, Stryer L. Biochemistry. 5th edition. New York: W H Freeman; 2002. Section 5.5, Amino Acids Are Encoded by Groups of Three Bases Starting from a Fixed Point. Available Here.

Image Courtesy:

1. “DNA RNA structure (full)” By Thomas Shafee – Own work (CC BY 4.0) via Commons Wikimedia   
2. “RNA-codon” By The original uploader was Sverdrup at English Wikipedia. (Public Domain) via Commons Wikimedia   
3. “Kooditabel” By Yersinia (Public Domain) via Commons Wikimedia   
4. “Ribosome mRNA translation en” By LadyofHats – Own work (Public Domain) via Commons Wikimedia  
5. “225 Peptide Bond-01” By OpenStax College – Anatomy & Physiology, Connexions Web site. (CC BY 3.0) via Commons Wikimedia