Question

When referring to a specific residue number of a given amino acid, which notation is commonly used?

a) Trp147
b) Trp147
c) Trp-147
d) Trp^147

Answer 1

The standard notation for referencing a specific amino acid residue is to use the three-letter abbreviation followed by the residue number, as in 'Trp147', without spaces or punctuation.

Step-by-step explanation:

When referring to a specific residue number of a given amino acid, the common notation used is 'Trp147' where the amino acid is represented by its three-letter abbreviation (in this case, Trp for tryptophan) followed by the residue number without any space or punctuation (as in option b). Hence, the correct answer is b) Trp147.

Amino acids in a polypeptide chain or a protein are typically denoted by either a three-letter abbreviation or a one-letter abbreviation. An example is Alanine, which is abbreviated as Ala or A, respectively. When describing the sequence of amino acids in a polypeptide or protein, the abbreviations are written consecutively from the N-terminus to the C-terminus, which represents the primary structure of the protein.