Path A - Module 24: Peptide Synthesis#

It is time to create your weapon. To fight the Alzheimer’s fibril, we need a small molecule that can “glue” to the aggregation core and stop the growth.

One of the most famous sequences for this is the KLVFF pentapeptide. In this module, you will learn to synthesize it from scratch using MolSysMT.

import molsysmt as msm
from molsysmt import systems

1. Simple Synthesis#

The function build_peptide() takes a sequence string and returns a complete 3D structure.

# Synthesize the KLVFF peptide
peptide = msm.build.build_peptide('KLVFF')

print(f"Peptide form: {msm.get_form(peptide)}")
msm.info(peptide)

2. Protecting the Ends (Cappings)#

In physiological conditions, peptides often need “caps” on their ends (N-terminal and C-terminal) to avoid unwanted charges or degradation. We can add ACE (Acetyl) and NME (N-Methyl) groups.

# Synthesize with caps
capped_peptide = msm.build.build_peptide('KLVFF', n_terminal='ACE', c_terminal='NME')

msm.info(capped_peptide, element='group')

3. Choosing the Secondary Structure#

You can specify if you want your peptide to start as an alpha-helix, a beta-strand, or a random coil.

# Build an alpha-helical version
helical_peptide = msm.build.build_peptide('KLVFF', configuration='alpha-helix')

msm.view(helical_peptide)

🏆 Path A Challenge: The Nano-Engineer#

  1. Synthesize a longer version of the peptide: KLVFFAL.

  2. Apply ACE and NME cappings.

  3. Set the initial configuration to beta-strand (which is the natural conformation in Amyloid fibrils).

  4. Use msm.get() to find the total number of atoms in your capped peptide.

You have created your therapeutic candidate! In Module 25, we will learn how to solvate our system: putting the fibril and the peptide in a realistic box of water.