Recombinant production of a functional SARS-CoV-2 spike receptor binding domain in the green algae Chlamydomonas reinhardtii

Anthony J Berndt; Tressa N Smalley; Bijie Ren; Ryan Simkovsky; Amr Badary; Ashley E Sproles; Francis J Fields; Yasin Torres-Tiji; Vanessa Heredia; Stephen P Mayfield

doi:10.1371/journal.pone.0257089

Recombinant production of a functional SARS-CoV-2 spike receptor binding domain in the green algae Chlamydomonas reinhardtii

PLoS One. 2021 Nov 18;16(11):e0257089. doi: 10.1371/journal.pone.0257089. eCollection 2021.

Affiliation

¹ Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America.

Abstract

Recombinant production of viral proteins can be used to produce vaccine antigens or reagents to identify antibodies in patient serum. Minimally, these proteins must be correctly folded and have appropriate post-translation modifications. Here we report the production of the SARS-CoV-2 spike protein Receptor Binding Domain (RBD) in the green algae Chlamydomonas. RBD fused to a fluorescent reporter protein accumulates as an intact protein when targeted for ER-Golgi retention or secreted from the cell, while a chloroplast localized version is truncated. The ER-retained RBD fusion protein was able to bind the human ACE2 receptor, the host target of SARS-CoV-2, and was specifically out-competed by mammalian cell-produced recombinant RBD, suggesting that the algae produced proteins are sufficiently post-translationally modified to act as authentic SARS-CoV-2 antigens. Because algae can be grown at large scale very inexpensively, this recombinant protein may be a low cost alternative to other expression platforms.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Chlamydomonas reinhardtii* / genetics
Chlamydomonas reinhardtii* / metabolism
Cloning, Molecular
Humans
Protein Interaction Domains and Motifs* / genetics
Protein Interaction Domains and Motifs* / immunology
Recombinant Proteins* / genetics
Recombinant Proteins* / immunology
Recombinant Proteins* / isolation & purification
Spike Glycoprotein, Coronavirus* / genetics
Spike Glycoprotein, Coronavirus* / immunology
Spike Glycoprotein, Coronavirus* / isolation & purification

Substances

Recombinant Proteins
Spike Glycoprotein, Coronavirus
spike protein, SARS-CoV-2

Grants and funding

AJB received Postdoctoral Fellowship funding from The Natural Sciences and Engineering Research Council of Canada (PDF-517259-2018). www.nserc-crsng.gc.ca SPM received Operating Grant funding from the U.S. Department of Energy as part PEAK (DEEE0008246). www.energy.gov The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.