The primary structure of a protein is determined by the specific sequence of amino acids linked together by covalent peptide bonds. This sequence is encoded by the gene corresponding to the protein in the organism's DNA. During gene expression, a specific sequence of nucleotides in DNA is transcribed into messenger RNA (mRNA), which is then translated by ribosomes to assemble amino acids in the precise order dictated by the genetic code. Thus, the DNA sequence directly dictates the linear amino acid sequence of the protein, which is its primary structure
. This sequence starts from the amino (N-) terminus to the carboxyl (C-) terminus of the polypeptide chain and is unique for each protein. The primary structure serves as the foundation for all higher levels of protein structure (secondary, tertiary, and quaternary) and ultimately determines the protein’s three-dimensional shape and function
. In summary:
- The primary structure is the linear sequence of amino acids in a protein.
- It is determined by the nucleotide sequence of the gene encoding the protein.
- The process involves transcription of DNA to mRNA and translation of mRNA into the amino acid chain.
- The amino acids are linked by peptide bonds.
- This sequence dictates the protein's folding and function.
Therefore, the gene sequence in DNA is the fundamental determinant of a protein's primary structure.
