Lipid of the Month

Each month we highlight a lipid of scientific interest. The LIPID MAPS® Lipid of the Month Archive lists lipids highlighted from 2015 - present.

January 2022

Lipid of the month Staphyloxanthin

When the Prince of Morocco In Shakespeare’s ‘The Merchant of Venice’ utters the often misquoted line “All that glisters is not gold” these are not his own words, but attributed to Death. January’s lipid of the Month, Staphyloxanthin is golden, but not gold, and the organism that produces it can cause death.  

Staphylococcus aureus is a serious human pathogen, frequently fatal in the pre-antibiotic era, and becoming increasingly so again as antibiotic resistance rises. The bacterium is named because of its golden colour, caused at least in part by staphyloxanthin, a carotenoid pigment.

Staphyloxanthin is a glucosyl ester of 4,4'-diaponeurosporen-4-oic acid, the glucose in turn esterified with 12-methyl tetradecanoic acid (anteisopentadecanoic acid). Initially, the alpha anomer of glucose was proposed1 but later work delineated the biosynthetic pathway and showed the more common beta form of glucose was present2.

Staphyloxanthin doesn’t exist just to make S. aureus look pretty on an agar plate. It has an antioxidant role in the cell, which may contribute to its virulence3. Thus drugs which inhibit staphyloxanthin synthesis could act as antibiotics. 

One of the early steps in formation of the carotenoid is the joining of two farnesyl diphosphate molecules, this is done by an enzyme very similar to one involved in the early steps of cholesterol biosynthesis in humans and  cholesterol-lowering drugs which inhibit this enzyme have been shown to inhibit staphyloxanthin formation too2. Very recently, a designed peptide antibiotic termed MSI-14 has been shown to have the same effect.

So while antibiotic resistance remains a major threat to human health, and it remains true that all that glisters is not gold, there remains more than a glister of hope for novel antibiotics.

References

Lipid of the Month Archive

2022
2021
2020
2019
2018
2017
2016
2015