A novel structure-based approach for identification of vertebrate susceptibility to SARS-CoV-2: implications for future surveillance programmes

Understanding the origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a highly debatable and unsolved challenge for the scientific communities across the world. A key to dissect the susceptibility profiles of animal species to SARS-CoV-2 is to understand how virus enters into the cells. The interaction of SARS-CoV-2 ligands (RBD on spike protein) with its host cell receptor, angiotensin-converting enzyme 2 (ACE2), is a critical determinant of host range and cross-species transmission. In this study, we developed and implemented a rigorous computational approach for predicting binding affinity between 299 ACE2 orthologs from diverse vertebrate species and the SARS-CoV-2 spike protein. The findings show that the spike protein of SARS-CoV-2 can bind to many vertebrate species carrying evolutionary divergent ACE2, implying a broad host range at the virus entry level, which may contribute to cross-species transmission and further viral evolution. Additionally, the present study facilitated the identification of genetic determinants that may differentiate susceptible from the resistant host species based on the conservation of ACE2- spike protein interacting residues in vertebrate host species known to facilitate SARS-CoV-2 infection; however, these genetic determinants warrant in vivo experimental confirmation. The molecular interactions associated with varied binding affinity of distinct ACE2 isoforms in a specific bat species were identified using protein structure analysis, implying the existence of diversified susceptibility of bat species to SARS-CoV-2. The findings from current study highlight the importance of intensive surveillance programs aimed at identifying susceptible hosts, particularly those with the potential to transmit zoonotic pathogens, in order to prevent future outbreaks.

Complementing the phenotypical spectrum of TUBA1A tubulinopathy and its role in early-onset epilepsies

TUBA1A tubulinopathy is a rare neurodevelopmental disorder associated with brain malformations as well as early-onset and intractable epilepsy. As pathomechanisms and genotype-phenotype correlations are not completely understood, we aimed to provide further insights into the phenotypic and genetic spectrum. We here present a multicenter case series of ten unrelated individuals from four European countries using systematic MRI re-evaluation, protein structure analysis, and prediction score modeling. In two cases, pregnancy was terminated due to brain malformations. Amongst the eight living individuals, the phenotypic range showed various severity. Global developmental delay and severe motor impairment with tetraparesis was present in 63% and 50% of the subjects, respectively. Epilepsy was observed in 75% of the cases, which showed infantile onset in 83% and a refractory course in 50%. One individual presented a novel TUBA1A-associated electroclinical phenotype with evolvement from early myoclonic encephalopathy to continuous spike-and-wave during sleep. Neuroradiological features comprised a heterogeneous spectrum of cortical and extracortical malformations including rare findings such as cobblestone lissencephaly and subcortical band heterotopia. Two individuals developed hydrocephalus with subsequent posterior infarction. We report four novel and five previously published TUBA1A missense variants whose resulting amino acid substitutions likely affect longitudinal, lateral, and motor protein interactions as well as GTP binding. Assessment of pathogenic and benign variant distributions in synopsis with prediction scores revealed sections of variant enrichment and intolerance to missense variation. We here extend the clinical, neuroradiological, and genetic spectrum of TUBA1A tubulinopathy and provide insights into residue-specific pathomechanisms and genotype-phenotype correlations.

In vivo mitochondrial matrix proteome profiling reveals RTN4IP1/OPA10 as an antioxidant NADPH oxidoreductase

Targeting proximity labeling enzymes to specific cellular locations is a viable strategy for profiling subcellular proteomes. Here, we generated transgenic mice expressing a mitochondrial matrix-targeted ascorbate peroxidase (MAX-Tg) to analyze tissue-specific matrix proteomes. Desthiobiotin-phenol labeling of muscle tissues from MAX-Tg mice allowed for efficient profiling of mitochondrial-localized proteins in these tissues. Comparative analysis of matrix proteomes from MAX-Tg muscle tissues revealed differential enrichment of mitochondrial proteins related to energy production in between different muscle groups. Reticulon 4 interacting protein 1 (RTN4IP1), also known as Optic Atrophy-10 (OPA10), was highly enriched in the cardiac and soleus muscles and was found to localize to the mitochondrial matrix via a strong mitochondrial targeting sequence at its N-terminus. Protein structure analysis revealed that RTN4IP1 is an NADPH oxidoreductase with structural homology to bacterial quinone oxidoreductase. Enzymatic activity assays, interactome analysis, and metabolite profiling confirmed a function for RTN4IP1 in coenzyme Q (CoQ) biosynthesis. Rtn4ip1-knockout C2C12 cells had reduced CoQ9 levels, were vulnerable to oxidative stress, and had decreased oxygen consumption rates and ATP production. Collectively, RTN4IP1 is a mitochondrial antioxidant NADPH oxidoreductase supporting oxidative phosphorylation activity in muscle tissue.

Training data composition affects performance of protein structure analysis algorithms

The three-dimensional structures of proteins are crucial for understanding their molecular mechanisms and interactions. Machine learning algorithms that are able to learn accurate representations of protein structures are therefore poised to play a key role in protein engineering and drug development. The accuracy of such models in deployment is directly influenced by training data quality. The use of different experimental methods for protein structure determination may introduce bias into the training data. In this work, we evaluate the magnitude of this effect across three distinct tasks: estimation of model accuracy, protein sequence design, and catalytic residue prediction. Most protein structures are derived from X-ray crystallography, nuclear magnetic resonance (NMR), or cryo-electron microscopy (cryo-EM); we trained each model on datasets consisting of either all three structure types or of only X-ray data. We find that across these tasks, models consistently perform worse on test sets derived from NMR and cryo-EM than they do on test sets of structures derived from X-ray crystallography, but that the difference can be mitigated when NMR and cryo-EM structures are included in the training set. Importantly, we show that including all three types of structures in the training set does not degrade test performance on X-ray structures, and in some cases even increases it. Finally, we examine the relationship between model performance and the biophysical properties of each method, and recommend that the biochemistry of the task of interest should be considered when composing training sets.

Neurodevelopmental Disorder With Microcephaly, Hypotonia, And Variable Brain Anomalies In A Consanguineous Iranian Family Is Associated With A Novel Homozygous Start Loss Variant In The PRUNE1 Gene

Background: Homozygous or compound heterozygous PRUNE1 mutations cause a neurodevelopmental disorder with microcephaly, hypotonia, and variable brain malformations (NMIHBA) (OMIM #617481). The PRUNE1 gene encodes a member of the phosphoesterase (DHH) protein superfamily that is involved in the regulation of cell migration. To date, most of the described mutations in the PRUNE1 gene are clustered in DHH domain. Methods: We subjected 4 members (two affected and two healthy) of a consanguineous Iranian family in the study. The proband underwent whole-exome sequencing and a novel identified variant was confirmed by Sanger sequencing. Co-segregation of the detected variant with the disease in family was confirmed.Results: By whole-exome sequencing, we identified the first start loss variant, NM_021222.3:c.3G>A; p.(Met1?), in the PRUNE1 in two patients of a consanguineous Iranian family with spastic quadriplegic cerebral palsy (CP), hypotonia, developmental regression, and cerebellar atrophy. Sanger sequencing confirmed the segregation of the variant with the disease in the family. Protein structure analysis also revealed that the variant probably leads to the deletion of DHH (Asp-His-His) domain, the active site of the protein, and loss of PRUNE1 function. Conclusion: We identified a novel start loss variant, NM_021222.3:c.3G>A; p.(Met1?) in the PRUNE1 gene in two affected members as a possible cause of NMIHBA in an Iranian family. We believe that the study adds a new pathogenic variant in spectrum of mutations in the PRUNE1 gene as a cause of PRUNE1-related syndrome.

Analysis of the SARS-CoV-2 envelope (E), nucleocapsid (N), and non-structural protein12 (nsp12) genes from COVID-19 patients in West Java

According to World Health Organization, as of January 2021, Indonesia is the only Southeast Asian country in which COVID-19 is still occurring in community transmission. West Java is one of the provinces holding the highest positive cases number. With the envelope (E), nucleocapsid (N), and non-structural protein 12 (nsp12) being the target genes of SARS-CoV-2 diagnostic kits and several antiviral drugs, the study of genetic variations has become relevant and greatly important. Out of 267 oro-nasopharyngeal swab specimens that were previously confirmed positive for COVID-19 in qPCR diagnostic test in Laboratorium Kesehatan Provinsi Jawa Barat, ten samples with acceptable qualities were selected and three samples were sequenced using Sanger sequencing. Nonsynonymous mutations were observed in the envelope gene (L21F) and in the nucleocapsid genes (R203K, G204R, A211S, and S193I). Phylogenetic analysis showed that samples were clustered with other sequences carrying identical mutations, but clustered non-discriminatively with all sequences when carrying no mutation. No pattern in geographical areas and clades, except for R203K-G204R for being a marker for the GR clade. Protein structure analysis showed that mutations observed did not change the hydrophobicity and the secondary structure of the nucleocapsid, while stability change (ΔΔG) showed that all mutations, aside from the R203K-G204R, have neutral effect on the protein stability. Therefore, it can be concluded that mutations observed in this experiment did not impart preference to disperse in certain geographical areas or cause any significant structural change in the protein.

Protein Structure Analysis and Prediction with Statistical Scoring Functions

The PDB database provides more than 150,000 entries for biological macromolecular structures [...]

Integrated Transcriptome-wide Profiling and Protein Structure Analysis of Pathogenic Genes in Venous Thromboembolism

BackgroundGenetic factors are considered to determine the balance of the coagulation and anticoagulation processes, yet the genetic variants related to venous thromboembolism (VTE) remain unclear. This study aimed to investigate the potential molecular mechanisms and pathogenic mutations associated with VTE by determining VTE-related differentially expressed genes (DEGs) by transcriptome-wide profiling and assaying protein structure in VTE.MethodsTwo gene expression datasets, GSE48000 and GSE19151, were accessed from the Gene Expression Omnibus (GEO) database to obtain gene expression data associated with VTE. We identified the DEGs between VTE patients and healthy people using R and performed functional enrichment analysis, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Then, whole-exome sequencing (WES) was performed for 25 VTE patients and 17 normal cases, and the structural locations of pathogenic missense mutations were identified using pyMOL. Finally, DGIdb database was used to select candidate drugs for the treatment of VTE.ResultsA total of 232 DEGs were identified from the GEO database. The significant function of these DEGs was mostly involved in RNA catabolic process and ribosome pathway. Notably, the results of WES for DEGs and protein structure analysis showed that Histamine N-Methyltransferase (HNMT) (chr2: 138759649 C>T, rs11558538) may be a main predisposing factor for VTE. In addition, Amodiaquine, Harmaline, Aspirin, Metoprine, Dabigatran, and Diphenhydramine were screened for VTE therapy.ConclusionThe results showed that HNMT (chr2: 138759649 C>T, rs11558538) may be potential target for the diagnosis and treatment of VTE.