The precise ordering of building blocks within a polypeptide chain, dictated by the messenger RNA (mRNA) sequence during protein synthesis, fundamentally defines the resulting protein’s identity and function. This specific linear sequence is established at the ribosome during the translation process, where transfer RNA (tRNA) molecules, each carrying a particular amino acid, recognize and bind to corresponding codons on the mRNA template. For example, an mRNA sequence of AUG-GCU-UAC will direct the sequential addition of methionine, alanine, and tyrosine, respectively, to the nascent polypeptide chain.
The significance of this arrangement lies in its direct impact on the protein’s three-dimensional structure and, consequently, its biological activity. A single alteration in the amino acid sequence can disrupt the protein’s folding pattern, leading to loss of function, altered function, or even aggregation and disease. Historically, understanding the relationship between amino acid sequence and protein function has been central to advancements in fields such as enzymology, structural biology, and drug discovery.
