This Molecule Spells “Happy Christmas”!

It’s Christmas Eve! I hope you’re all getting to enjoy the festivities in some way, whether you’re taking a break from research/work with family and friends or taking advantage of it being quiet to get work done – or a special shout out if you’re one of the superheroes that keep the emergency services running over the Christmas/New Year period.

In true chemistry-geek fashion, I’d like to wish you a very Happy Christmas with this molecule!

MERRYCHRISTMASunlabelled
A Christmassy peptide

It might not look like it says much at first but let me explain the structure in a bit more detail. This is a peptide, that is a long chain molecule made up of individual amino acid components. The amino acid “links” are connected by amide bonds.

amide bond formation
An amide bond forms between an amino (NH2) and a carboxylic acid (COOH)

Amino acids are used to build hundreds of thousands of proteins that carry out many jobs in our bodies. There are 20 common amino acids which are typically found in biology and 9 of those are “essential amino acids”, meaning they can only be obtained by our diet and not synthesised by our own bodies.

The 20 amino acids can be categorised by their chemical structure. While all possess an amine (NH2) and a carboxylic acid group (COOH), hence the name “amino acid”, they contain side chains that branch off a central atom between the amine and acid groups.

These side chains can be categorised as to whether they contain a greasy aliphatic group of atoms or something containing an alcohol, sulfur, acidic or basic group. Andy Brunning’s infographic summarises this really nicely.

20 Common Amino Acids Physiological [EDIT].png
Amino Acid summary produced by Andy Brunning of Compound Interest
Because peptides are lengthy sequences of amino acids, its easier to abbreviate the individual amino acid chains with individual letters to succinctly describe the amino acids present within a protein:

H – histidine, a basic amino acid containing an imidazole heterocycle (ring of atoms that isn’t just made up of carbons and hydrogens)

A – alanine, one of the simpler aliphatic amino acids with just a methyl side chain

P – proline, the only amino acid that incorporates the amino acid motif into the side chain.

P – another proline

Y – tyrosine, an aromatic amino acid (contains a hexagonal benzene ring) with an alcoholic phenol OH attached.

C – cysteine, the other sulfur-containing amino acid

H – histidine, another basic amino acid

R – another arginine

I – isoleucine. Leucine is a straight chain of three carbons. Isoleucine is an “isomer” of leucine, meaning those atoms are arranged slightly differently

S – serine, an alcoholic amino group

T – threonine, the third of the three alcohol containing amino acids (serine, threonine and tyrosine). It has a slightly longer carbon chain than serine. The kinase proteins I’m trying to target in my PhD reacts with these kinds of residues in our cells.

M – another methionine

A – another alanine

S – a final alcoholic serine caps the end of our festive molecule

With that, I’d like to thank you all for following my scientific escapades so far and wish you all a Christmas period full of peace and joy and all the best for 2019.

MERRYCHRISTMASLabelled
My labelled festive peptide wishing you a HAPPY CHRISTMAS

How are you celebrating Christmas? Do you have any fun abbreviations in your work? Let me know in the comments below.

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