T83A

T83A is a designation used in molecular biology to denote a specific amino acid substitution in a protein: the threonine at position 83 is replaced by alanine. The notation follows the standard convention in protein mutation reporting, where the initial letter represents the wild-type amino acid, the number indicates the residue position, and the final letter identifies the mutant amino acid.

The exact effect of a T83A substitution depends on the protein and its context. Because threonine bears a hydroxyl group, replacing it with alanine removes this functional group, which can influence phosphorylation if that residue is normally modified, as well as local hydrogen bonding, polarity, and steric environment. The mutation can affect protein folding, stability, catalytic activity, substrate or partner binding, or interaction networks, and may be neutral in some proteins while deleterious in others.

In research, T83A is typically introduced by site-directed mutagenesis to study the role of that specific residue. Researchers then compare the mutant to the wild type using biochemical assays, structural analyses, cellular localization studies, or phenotypic measurements to infer the residue’s function.

Not all T83A substitutions have clinical significance; their relevance is determined by the protein, organism, and biological pathway involved. T83A is primarily a descriptive notation used to catalog and discuss a particular missense variant in scientific literature and database entries.

See also: missense mutation, amino acid substitution, site-directed mutagenesis, protein function.