bioRxiv Science⌕ Search

bioRxiv · 10.1101/2020.12.01.406637

Evolution of the SARS-CoV-2 proteome in three dimensions (3D) during the first six months of the COVID-19 pandemic

Abstract

Three-dimensional structures of SARS-CoV-2 and other coronaviral proteins archived in the Protein Data Bank were used to analyze viral proteome evolution during the first six months of the COVID-19 pandemic. Analyses of spatial locations, chemical properties, and structural and energetic impacts of the observed amino acid changes in >48,000 viral proteome sequences showed how each one of the 29 viral study proteins have undergone amino acid changes. Structural models computed for every unique sequence variant revealed that most substitutions map to protein surfaces and boundary layers with a minority affecting hydrophobic cores. Conservative changes were observed more frequently in cores versus boundary layers/surfaces. Active sites and protein-protein interfaces showed modest numbers of substitutions. Energetics calculations showed that the impact of substitutions on the thermodynamic stability of the proteome follows a universal bi-Gaussian distribution. Detailed results are presented for six drug discovery targets and four structural proteins comprising the virion, highlighting substitutions with the potential to impact protein structure, enzyme activity, and functional interfaces. Characterizing the evolution of the virus in three dimensions provides testable insights into viral protein function and should aid in structure-based drug discovery efforts as well as the prospective identification of amino acid substitutions with potential for drug resistance.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Lubin, J. H., Zardecki, C., Dolan, E. M., Lu, C., Shen, Z., Dutta, S., Westbrook, J. D., Hudson, B. P., Goodsell, D. S., Williams, J. K., Voigt, M., Sarma, V., Xie, L., Venkatachalam, T., Arnold, S., Alfaro Alvarado, L. H., Catalfano, K., Khan, A., McCarthy, E., Staggers, S., Tinsley, B., Trudeau, A., Singh, J., Whitmore, L., Zheng, H., Benedek, M., Currier, J., Dresel, M., Duvvuru, A., Dyszel, B., Fingar, E., Hennen, E. M., Kirsch, M., Khan, A. A., Labrie-Cleary, C., Laporte, S., Lenkeit, E., Martin, K., Orellana, M., Ortiz-Alvarez de la Campa, M., Paredes, I., Wheeler, B., Rupert, A., Sam, A. 2020-12-01. Evolution of the SARS-CoV-2 proteome in three dimensions (3D) during the first six months of the COVID-19 pandemic. https://doi.org/10.1101/2020.12.01.406637

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Fatty Acid Synthase Binds Cellular mRNAs and its Depletion Reduces Translational Efficiency

Metabolic enzymes with non-canonical RNA binding activity have drawn a growing interest, due to their implications for basic biology and disease. Here we present the first endogenous RNA interactome of fatty acid synthase (FASN), an emerging oncological and virological target. Utilizing crosslinking-based approaches, we characterize the direct RNA association of FASN in two human cell lines, identifying over 6000 binding sites across over 3500 protein-coding genes, with a striking preference for the 5' UTR. We provide a functional cross-screen on the effects of FASN depletion on cellular translation. This integration with ribosome profiling indicated a preferential reduction in the translational efficiencies of FASN-associated mRNAs - an effect shown to be dependent on binding location and site number. Associated transcripts were enriched for morphogenic and cell division-related functions, as well as palmitoylated proteins. This correlative work primes further investigation of FASN as a regulator of translation of its target mRNAs.

molecular biology↗

Genomic features and instability of linezolid resistance in vancomycin-resistant Enterococcus faecalis ST525

This study investigated the mechanisms of oxazolidinone resistance and genomic background in clinical ST525 Enterococcus faecalis isolates, a poorly characterized lineage reported in Brazilian hospitals as either vancomycin-resistant (VRE) or linezolid- and vancomycin-resistant (LVRE). Five LVREfs from intensive care unit patients (linezolid MICs, 8-32 mg/L; vancomycin MICs, >256 mg/L) carried only G2576T and G2505A (in three of four rrl copies) as known linezolid resistance determinants, despite variable linezolid MICs. During serial in vitro passages without antibiotic pressure, isolates with initial MICs of 8-16 mg/L exhibited progressive MIC reductions accompanied by reversion of mutant to wild-type rrl copies, whereas the isolate with an initial MIC of 32 mg/L maintained high-level resistance without reversion. Additional domain V substitutions emerged during MIC decline, while growth kinetics remained broadly similar. Whole-genome sequencing of a representative isolate (LVREfs L7) revealed a ~2.8-Mb chromosome enriched in mobile genetic elements (~8.6%), lacking a functional CRISPR-Cas system. A plasmid-borne prototype Tn1546 carrying vanA, devoid of internal insertion sequences, was found inserted into a Tn3-family transposase gene, a platform not typically associated with vanA mobilization. Together, these findings indicate that ST525 LVREfs, whose genomic features are consistent with long-term persistence in hospitals, may pose a challenge to routine susceptibility testing. A single mutational mechanism can yield variable linezolid MICs, and the ratio of mutated vs wild-type rrl copies can become heterogeneous in the absence of antibiotic pressure, without correlating directly with these values, contrary to the well-documented copy number-MIC correlation.

molecular biology↗

Global repression of mesenchymal genes in epithelial cells by the histone demethylase LSD1

Epithelial-mesenchymal transition (EMT) is an essential process in development, tissue repair, and tumour metastasis, and is triggered by SNAI, ZEB and TWIST transcription factors, that recruit lysine-specific demethylase 1 (LSD1) to repress epithelial genes such as E-cadherin. In mesenchymal cells, LSD1 inhibition restores E-cadherin expression and reduces migration and invasion, consistent with LSD1 inhibition reverting EMT, and offering a therapeutic modality for EMT-associated disease. Recent data, however, suggest context-dependent roles for LSD1, as its inhibition in epithelial cells increases mesenchymal marker expression, potentially promoting EMT. To investigate this discrepancy, we mapped genome-wide binding of LSD1 in HCT116 epithelial cells and used rapid degron-mediated ablation of endogenous LSD1 to measure changes in nascent and steady-state transcription and chromatin accessibility. In epithelial cells, LSD1 binds constitutively-accessible, primed mesenchymal promoters. These are rapidly derepressed after LSD1 ablation, with activation of SNAI2 and ZEB1, which repress epithelial hallmarks such as E-cadherin. Re-introduction of LSD1 downregulates SNAI2 and ZEB1 but, surprisingly, further represses E-cadherin, indicating sustained loss of epithelial characteristics. Collectively, our results show that LSD1 maintains epithelial identity by repressing mesenchymal genes, questioning the therapeutic utility of LSD1 inhibition for EMT control.

molecular biology↗