Peptidyle

Deduce the pentapeptide sequence

Peptide solving tips

Guess: Enter

How to solve the peptide puzzle

A pentapeptide is made up of 5 amino acids. The figure above shows one such peptide chain with an unknown sequence. Your task is to find out the sequence of this pentapeptide.

Here is a step by step guide to help you:

1. Looking at an amino acid guide can help. Here is a PDF guide: bchm_exam-help_sheet.pdf . You can also search online for an image of "amino acid one-letter code chart" to see all 20 amino acids with their single letter codes.
2. First, identify the amino terminal end, which is represented as NH₃⁺ and highlighted in bright green. It is important to differentiate between the general nitrogens found in amino acid backbones (denoted as NH) and the nitrogen in the side chains of amino acids. Among amino acids, only lysine has a side chain with three hydrogens, resembling the NH₃⁺ of the amino terminal end.
3. The peptide bonds are highlighted in bright green, helping you see the different amino acids.
4. Look at the side chains of each amino acid to figure out their single letter amino acid code.
5. Once you know the single letter codes for the 5 side chains, list them in the amino to carboxyl (N→C) direction. This is the accepted way to write peptide sequences.
6. The correct sequence of letters will be a five letter English word. This word is also an answer in the New York Times Wordle™ game.