Y145M

Y145M is a shorthand notation used in molecular biology to denote a missense mutation in which the amino acid tyrosine (Y) at position 145 of a protein is substituted with methionine (M). The notation is used across proteins; the exact residue numbering is tied to a reference sequence and may vary between isoforms.

In genetics and proteomics, Y145M can arise from a single-nucleotide change in the corresponding gene coding sequence. The chemical shift from a polar aromatic residue to a nonpolar sulfur-containing residue can have diverse effects depending on the protein context, such as altering catalytic activity, substrate binding, stability, or interactions with other molecules.

Because tyrosine can be involved in phosphorylation and hydrogen bonding, replacing it with methionine may remove such regulatory features and change local structure. However, many Y145M substitutions are tolerable, especially if the residue resides in a nonessential region or if compensatory interactions exist. Functional impact is usually assessed experimentally or predicted with computational tools, considering conservation, structural environment, and biochemical properties.

Y145M is commonly reported in scientific literature about mutational analyses, disease-related studies, or engineered variants. It is important to confirm the reference sequence and residue numbering when interpreting reports, as Y145M in one protein may correspond to a different position in another due to alternative splicing or isoforms.

See also: missense mutation, protein sequence, single-nucleotide polymorphism.