Difference Between Base Sequence and Amino Acid Sequence

The key difference between base sequence and amino acid sequence is that base sequence is the nucleotide sequence of a DNA or an RNA molecule, while the amino acid sequence is the string of amino acids linked together in a peptide or a protein.

DNA and RNA are the major nucleic acids found in living organisms. DNA stores genetic information of an organism. Thus, most of the living organisms have genomes composed of DNA. A gene or a specific nucleotide fragment of a chromosome encodes for a protein. Genetic code is hidden in the nucleotide sequence of a gene. During gene expression, base sequence transcribes and then translates into an amino acid sequence of a protein.

CONTENTS

1. Overview and Key Difference
2. What is a Base Sequence
3. What is an Amino Acid Sequence
4. Similarities Between Base Sequence and Amino Acid Sequence
5. Side by Side Comparison – Base Sequence vs Amino Acid Sequence in Tabular Form
6. Summary

What is a Base Sequence?

Nucleotides are the building blocks of DNA and RNA. Deoxyribonucleotides make DNA while ribonucleotides make RNA. Each nucleotide has a nitrogenous base, pentose sugar and a phosphate group. Base is the component that differs between four types of nucleotides. Hence, nucleotides are named according to the bases. In other words, the base sequence of a nucleic acid represents the nucleotide sequence of it.

Figure 01: Base Sequence

Generally, base sequences carry genetic information of the cell. The nucleotide sequences can be written using the first letter of the bases of nucleotides such as adenine (A), thymine (T), guanine (G) and cytosine (C) in DNA sequences. In RNA sequences, nucleotide sequences are adenine (A), uracil (U), guanine (G) and cytosine (C)

What is an Amino Acid Sequence?

An amino acid sequence is the string of amino acids of a peptide or a protein. Thus, amino acids are the building blocks of proteins. Amino acid sequence originates from an mRNA sequence. mRNA sequence originates as a result of the transcription of a gene in which the order of the nucleotides in the coding sequence decides the resulting protein. Three nucleotides collectively make a codon, which in turn decides the amino acid. Thus, each grouping of three DNA nucleotide bases is a code for a specific amino acid. For example, the DNA nucleotide base sequence CTG codes for the amino acid leucine. Likewise, there are 64 possible codons to decide twenty amino acids. Ultimately, a unique amino acid sequence gives a specific protein.

Figure 02: Amino Acid Sequence

The amino acid sequence is the key factor that determines the structure and three-dimensional shape of the protein. It is because each amino acid has unique properties that decide its role in the protein.

What are the Similarities Between Base Sequence and Amino Acid Sequence?

• Base sequence and amino acid sequence are the strings of monomers of DNA and protein, respectively.
• The base sequence of DNA codes for the sequence of amino acids in a polypeptide chain, which forms a protein.
• Grouping of three DNA nucleotide bases makes a specific codon that codes for a specific amino acid.

What is the Difference Between Base Sequence and Amino Acid Sequence?

Base sequence is the string of nucleotides of a DNA or RNA while the amino acid sequence is the string of amino acids of a protein. So, this is the key difference between base sequence and amino acid sequence. Furthermore, there are four different types of nucleotides in a base sequence, while there are twenty different amino acids in an amino acid sequence.

Moreover, a further difference between base sequence and amino acid sequence is that the base sequences can exist as double-stranded, while the amino sequences do not exist as double-stranded.

Below infographic shows more differences between base sequence and amino acid sequence.

Summary – Base Sequence vs Amino Acid Sequence

Base sequence and amino acid sequence are two related sequences since the grouping of three nucleotides in the base sequence codes for an amino acid. Hence, the base sequence is the sequence that contains the genetic code of the amino acid sequence. In fact, the base sequence is the monomer sequence of DNA or RNA, while the amino acid sequence is the monomer sequence of a protein. So, this summarizes the difference between base sequence and amino acid sequence.

Reference:

1. Berg, Jeremy M. “Amino Acids Are Encoded by Groups of Three Bases Starting from a Fixed Point.”Biochemistry. 5th Edition., U.S. National Library of Medicine, 1 Jan. 1970, Available here.
2. “Nucleic Acid Sequence.” Wikipedia, Wikimedia Foundation, 6 Mar. 2019, Available here.

Image Courtesy:

1. “DNA sequence” By Sjef – Own work (Public Domain) via Commons Wikimedia
2. “Aasequencedirection*” By Lizanne Koch – lgkoch – own work with ChemBioDraw (Public Domain) via Commons Wikimedia

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