Deactivation

This work is freely available with a CC-BY-4.0 license.
For use of this image, please acknowledge “Sarah Iannucci”.

We are all told that good hand-washing habits can help to stop the spread of COVID-19, but how exactly does this work?

“Deactivation” is a gouache painting showing the process by which soap surfactants interact with the viral envelope of SARS-CoV-2, tearing apart the structure and rendering the virus inactive. As we scrub our hands with soap, these surfactants are brought into contact with the viral membrane. Soap surfactants have a hydrophilic (or water-loving) head and a hydrophobic (or water-hating) tail. The viral membrane has this configuration too, with the hydrophilic heads facing outward and the hydrophobic tails facing inward; this is the basis for plasma membrane formation.  As the surfactant tails encounter the hydrophobic core of the viral membrane, they begin to insert themselves, compromising the viral membrane integrity and leading to the formation of micelles. The surfactants are also attracted to other proteins within the membrane, such as the characteristic spike proteins. Eventually, the membrane is torn apart, the proteins disperse, and the viral contents are exposed. Thus, the simple action of washing our hands regularly and efficiently can effectively render the SARS-CoV-2 virion inactive by this process.

This piece was created for CellSpace, a guided workshop for cellular and molecular SciArt with scientific illustrator David Goodsell. The topic for this workshop was to explore the science of COVID-19 with final works to be featured in the digital art show “New Ways of Living: Understanding the Science of COVID-19". The final works were presented at the SigmaXi SciCommMake competition. Please visit the "New Ways of Living" website to view all published works by clicking here or alternatively visiting www.NWoLCovid19.com/.

The high-resolution image can be downloaded here

Scroll below for structural justifications and references used in the creation of this piece.

Structural Justifications

All measurements, detailed below, are proportional and were blown up to fit across two A3 sized sheets. The average diameter of 100 nm was used for the SARS-CoV-2 virion in this piece (Ke et al. 2020). For the viral lumen, I selected a diameter of 80 nm (Yao et al. 2020). Because of these measurements, the viral envelope was created at 10 nm, with individual phospholipids being about 5 nm in length.

 The spike protein ectodomain is around 20 nm in length (Yao et al. 2020). On average, there are 26 spike proteins per virion (Yao et al. 2020). As this is a cross-section, I used half of this number for my piece, with several spike proteins being depicted as further back. It is known that the spikes are not uniformly distributed, with the majority having the receptor binding domain (RBD) in the closed conformation (Ke et al. 2020). It has been shown that the spike proteins rotate freely around their stalks, leaning anywhere up to 90 degrees relative to the envelope’s normal axis – though it seems that tilts over 50 degrees are not as favorable (Ke et al. 2020).

 The ribonucleoproteins (RNPs) were shown to have an average diameter of 15 nm, with the majority in hexon formation (Yao et al. 2020). The cartoon-like depiction of the N protein and RNA was derived from the structures provided by Zeng et al. 2020.

There are an estimated 2000 copies of the membrane protein homodimers, which help to define the viral envelope shape (Bar-On et al. 2020). They appear to resemble the shape of a Greek amphora, with the endodomains making close but not direct contact (Neuman and Buchmeier, 2016). The membrane proteins are enlongated and make contact with the underlying RNPs, which help to stabilize the virion (Neuman et al. 2016; Schoeman and Fielding, 2019).

There are an estimated 20 copies of the envelope proteins in the viral membrane (Bar-On et al. 2020). These proteins form pentamers that possibly have ion channel activity (Pervushin et al. 2009). As only a small portion are incorporated into the viral envelope, I have added only three to my piece (Schoeman and Fielding, 2019).

The surfactant micelles are generally spherical and 2-3 nm in length (Attwood and Florence, 2012). I chose to make the surfactants slightly larger than this (about 5 nm) to show balance in the interaction with the phospholipids. The phospholipid-surfactant interaction was depicted in multiple stages and as dynamic, as micelles are continually formed and broken down (Attwood and Florence, 2012). Inspiration for this interaction was also drawn from the RCSBProteinDataBank Youtube video “Fighting Coronavirus with Soap”, INVIVO’s online video “COVID-19 and the Science of Soap”, and ABCScience’s online video “How does soap destroy coronaviruses?”.

References

Attwood, David, and Alexander T. Florence. Physical Pharmacy. London, Pharmaceutical Press, 2012. 

Bar-On, Yinon M., et al. "Science Forum: SARS-CoV-2 (COVID-19) by the numbers." Elife 9 (2020): e57309.

“COVID-19 and the Science of Soap” INVIVO, 22 October 2020, https://invivo.com/covid-19-and-the-science-of-soap/

“Fighting Coronavirus with Soap” YouTube, uploaded by RCSBProteinDataBank, 22 October 2020, www.youtube.com/watch?v=s2EVlqql_f8&app=desktop.

“How does soap destroy coronaviruses?” Facebook, uploaded by ABCScience, 22 October 2020, https://www.facebook.com/ABCScience/videos/2615493995446740.

Ke, Zunlong, et al. "Structures and distributions of SARS-CoV-2 spike proteins on intact virions." Nature (2020): 1-7.

Neuman, Benjamin W., and Michael J. Buchmeier. "Supramolecular architecture of the coronavirus particle." Advances in virus research. Vol. 96. Academic Press, 2016. 1-27. 

Peng, Ya, et al. "Structures of the SARS‐CoV‐2 nucleocapsid and their perspectives for drug design." The EMBO Journal (2020): e105938. 

Pervushin, Konstantin, et al. "Structure and inhibition of the SARS coronavirus envelope protein ion channel." PLoS Pathog 5.7 (2009): e1000511.

Schoeman, Dewald, and Burtram C. Fielding. "Coronavirus envelope protein: current knowledge." Virology journal 16.1 (2019): 1-22.

Yao, Hangping, et al. "Molecular architecture of the SARS-CoV-2 virus." Cell (2020).

Zeng, Weihong, et al. "Biochemical characterization of SARS-CoV-2 nucleocapsid protein." Biochemical and biophysical research communications (2020).