Thr183Tyr185

Thr183Tyr185 is a protein variant designation used in biochemistry and genomics to describe a specific pattern of amino acid substitutions at residue positions 183 and 185 in a given protein sequence. The exact protein, organism, and reference sequence are determined by the context in which the notation appears.

The notation suggests two changes: at position 183, threonine (Thr) is replaced by tyrosine (Tyr), written as Thr183Tyr. The trailing "Tyr185" indicates that the residue at position 185 in the variant is tyrosine, implying a second substitution from the reference residue to Tyr at 185, though the precise interpretation can vary by database convention.

Identification and annotation: Thr183Tyr185 is identified through DNA sequencing, protein sequencing, or site-directed mutagenesis studies. It may be recorded in protein variant databases or literature as a double substitution for a single protein in a specific species, or used descriptively in research reports.

Functional considerations: Substitutions to tyrosine introduce an aromatic side chain that can affect local packing, hydrogen bonding, phosphorylation sites, or interaction surfaces. The functional impact is highly context dependent, potentially altering stability, folding, catalytic activity, or partner binding. Computational tools offer rapid predictions but experimental validation is essential.

Clinical and evolutionary context: If associated with disease, reports describe phenotypic effects, penetrance, and inheritance; otherwise the variant may be catalogued as a benign polymorphism or of unclear significance. For researchers, Thr183Tyr185 highlights the importance of protein context when interpreting substitutions.