Binding of SARS-CoV-2 Structural Proteins to Hemoglobin and Myoglobin Studied by SPR and DR LPG.

One of the first clinical observations related to COVID-19 identified hematological dysfunctions. These were explained by theoretical modeling, which predicted that motifs from SARS-CoV-2 structural proteins could bind to porphyrin. At present, there is very little experimental data that could provide reliable information about possible interactions. The surface plasmon resonance (SPR) method and double resonance long period grating (DR LPG) were used to identify the binding of S/N protein and the receptor bind domain (RBD) to hemoglobin (Hb) and myoglobin (Mb). SPR transducers were functionalized with Hb and Mb, while LPG transducers, were only with Hb. Ligands were deposited by the matrix-assisted laser evaporation (MAPLE) method, which guarantees maximum interaction specificity. The experiments carried out showed S/N protein binding to Hb and Mb and RBD binding to Hb. Apart from that, they demonstrated that chemically-inactivated virus-like particles (VLPs) interact with Hb. The binding activity of S/N- and RBD proteins was assessed. It was found that protein binding fully inhibited heme functionality. The registered N protein binding to Hb/Mb is the first experimental fact that supports theoretical predictions. This fact suggests another function of this protein, not only binding RNA. The lower RBD binding activity reveals that other functional groups of S protein participate in the interaction. The high-affinity binding of these proteins to Hb provides an excellent opportunity for assessing the effectiveness of inhibitors targeting S/N proteins.

Morphofunctional Characteristics of Erythrocytes and Blood Erythropoietin Level in Patients as Predictors of Severe Course of COVID-19.

Morphological and functional characteristics of erythrocytes, hemoglobin, and erythropoietin level in the venous blood were evaluated by laser interference microscopy, Raman spectroscopy with a short-focus extreme aperture lens monochromator, and by ELISA, respectively, in 30 patients with verified moderate COVID-19 at the time of hospitalization and 30 healthy volunteers. The patients whose course of COVID-19 has worsened to critical by day 5 had already had lower (p<0.001) indicators at the time of hospitalization such as the area and thickness of erythrocytes, the hemoglobin distribution and packing density, hemoglobin conformation index (I1355/I1550)/(I1375/I1580) reflecting its oxygen affinity, and blood erythropoietin content. Our findings suggest that these characteristics of erythrocytes, hemoglobin, and erythropoietin can serve as potential predictors of COVID-19 aggravation in hospitalized patients.

COVID-19: beta-thalassemia subjects immunised?

The novel coronavirus pneumonia (COVID-19) is a contagious acute respiratory infectious disease whose causative agent has been demonstrated to be a novel virus of the coronavirus family, SARSCoV-2. A recent PRE-print study has showed a heme attack on the 1-beta chain of hemoglobin by COVID19. Beta-thalassemia results of a default in the hemoglobin beta-chain synthesis. 1,5% global population are heterozygotes for this disease. In this study, by a multiple linear regression, we have analyzed the evolution of COVID-19 infection in three Italian regions (Puglia, Sardinia, Sicilia) with different beta-thalassemic prevalences, in order to search a link. The results have showed that betathalassemic heterozygote population prevalence is correlated to immunity against COVID-19, by a regression. This paper is only for academic discussion, the hypotheses and conclusions needs to be confirmed by further research.