Phe105Met106

Phe105Met106 is a designation used in protein science to refer to a variant involving residues at positions 105 and 106 of a protein sequence. In many reports, Phe105Met denotes a substitution where phenylalanine (Phe) at position 105 is replaced by methionine (Met). The trailing 106 is typically used to indicate the neighboring residue or to signal a second mutation at position 106 in the same variant; the exact meaning depends on the authors’ naming convention and should be clarified in the primary source.

The notation is commonly encountered in mutagenesis studies aimed at probing structure–function relationships. Because positions 105 and 106 often lie within a hydrophobic core or a binding interface in many proteins, substitutions at these sites can influence protein stability, folding kinetics, and interaction with ligands or substrates. Depending on the local environment, a Phe to Met change can alter side-chain packing, aromatic interactions, or conformational dynamics, potentially shifting catalytic activity, binding affinity, or thermal stability.

Characterization of such a variant typically involves site-directed mutagenesis to introduce the substitutions, followed by expression, purification, and a suite of assays. Functional tests (e.g., enzymatic activity or binding assays), thermostability measurements, and structural analyses (X-ray crystallography, cryo-EM, or NMR) help determine the impact. Computational modeling and sequence conservation analyses are often used in parallel to interpret observed effects and guide further engineering.

In summary, Phe105Met106 denotes a targeted mutational study at two adjacent positions, with outcomes varying by protein context and experimental design.