The Spike's Significant Sequence?

Arg-Gly-Asp (RGD) peptides are of interest in numerous therapeutic areas such as cancer, angiogenesis, antithrombosis, and more. RGDs are found naturally in several places, including within bone sialoprotein (SGP), transforming growth factor beta (TGFß), in cell adhesive extracellular matrix (ECM) proteins, and as disintegrins in viper venoms, to name a few. The sequence also happens to be contained within the spike protein (S protein) of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). Important for binding to the RGD-integrins, the sequence is a cell attachment site for many proteins and is involved in many cell processes including cell proliferation and differentiation.1 RGD structure

Like other coronaviruses, SARS-CoV-2 uses its spike proteins to gain entry into host cells. Angiotensin converting enzyme 2 (ACE2) and serine protease type II transmembrane serine protease (TMPRSS2) are two locations of entrance. A few interesting new publications highlight that, with an RGD-sequence on its S protein, there is a possibility that SARS-CoV-2 may also use the integrins to gain cell entry. The tripeptide is located within the section of the receptor binding domain that binds to human ACE2 (amino acids 437-508). Other types of viruses use integrin binding, so it is not unusual for SARS-CoV-2 to have it within its arsenal. Blocking integrin binding may be a viable route for neutralizing the virus.2,3


  1. C.-C. Sun, X.-J. Qu, & Z.-H. Gao, American Journal of Therapeutics, 23, e198 (2016). Abstract retrieved from
  2. A Potential Role for Integrins in Host Cell Entry by SARS-CoV-2.
  3. An Evolutionary RGD Motif in the Spike Protein of SARS-CoV-2 May Serve as a Potential High Risk Factor for Virus Infection? (pre-print)
Industry News , Biologically Active Peptides , Cellular , Infectious Diseases , Coronavirus (COVID-19)

Denise Karounos

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Denise Karounos joined Peptides International in October 2016. After completing her BS in chemistry from West Virginia University, she spent time as an organic chemist at Bachem Bioscience synthesizing peptides and amino acid derivatives. Denise has experience with both solid and solution-phase peptide synthesis, and has worked under both research and cGMP settings. After completion of her MBA at Saint Joseph’s University, Denise transitioned into product management of peptides and amino acid derivatives. Denise has spent her time at PI focusing on both sales and marketing, including quoting, product management, market research and sales analysis, generating technical marketing content, and attending industry conferences.