Impact of single amino acid substitution on the structure and function of TANK-binding kinase-1

Investigating the role of thymol as a promising inhibitor of pyruvate dehydrogenase kinase 3 for targeted cancer therapy

Protein kinases have emerged as major contributors to various diseases. They are currently exploited as a potential target in drug discovery because they play crucial roles in cell signaling, growth, and regulation. Their dysregulation is associated with inflammatory disorders, cancer, and neurodegenerative diseases. Pyruvate dehydrogenase kinase 3 (PDK3) has become an attractive drug target in cancer therapeutics. In the present study, we investigated the effective role of thymol in PDK3 inhibition due to the high affinity predicted through molecular docking studies. Hence, to better understand this inhibition mechanism, we carried out a 100 ns molecular dynamics (MD) simulation to analyse the dynamics and stability of the PDK3-thymol complex. The PDK3-thymol complex was stable and energetically favourable, with many intramolecular hydrogen bond interactions in the PDK3-thymol complex. Enzyme inhibition assay showed significant inhibition of PDK3 by thymol, revealing potential inhibitory action of thymol towards PDK3 (IC50 = 2.66 μM). In summary, we established thymol as one of the potential inhibitors of PDK3, proposing promising therapeutic implications for severe diseases associated with PDK3 dysregulation. This study further advances our understanding of thymol's therapeutic capabilities and potential role in cancer treatment.

Therapeutic targeting of microtubule affinity-regulating kinase 4 in cancer and neurodegenerative diseases

Microtubule affinity-regulating kinase 4 (MARK4) is a member of the Ser/Thr protein kinase family, phosphorylates the microtubule-connected proteins and plays a vital role in causing cancers and neurodegenerative diseases. This kinase modulates multiple signaling pathways, including mammalian target of rapamycin, nuclear factor-κB, and Hippo-signaling, presumably responsible for cancer and Alzheimer's. MARK4 acts as a negative controller of the Hippo-kinase cassette for promoting YAP/TAZ action, and the loss of MARK4 detains the tumorigenic properties of cancer cells. MARK4 is involved in tau hyperphosphorylation that consequently affects neurodegeneration. MARK4 is a promising drug target for cancer, diabetes, and Alzheimer's. Developing the potent and selective inhibitors of MAKR4 are promising in the therapeutic management of associated diseases. Despite its great significance, a few reviews are available to discuss its structure, function and clinical significance. In the current review, we aimed to provide detailed information on the structural features of MARK4 targeted in drug development and its role in various signaling pathways related to cancer and neurodegenerative diseases. We further described the therapeutic potential of MARK4 inhibitors in preventing numerous diseases. Finally, the updated information on MARK4 will be helpful in the further development of effective therapeutic molecules.

Dynamics of TUBB protein with five majorly occurring natural variants: a risk of cortical dysplasia

Beta-tubulin (TUBB) protein is one of the components of the microtubule cytoskeleton that plays a critical role in the central nervous system. Genetic variants of TUBB cause cortical dysplasia, a developmental brain defect implicated in axonal guidance and the neuron migration. In this study, we assess pathogenic variants (Q15K, Y222F, M299V, V353I, and E401K) of TUBB protein and compared with non-pathogenic variant G235S to determine their impact on protein dynamic to cause cortical dysplasia. Among the analyzed variants, Q15K, Y222F, M299V, and E401K were noticed to have deleterious effect. Then, variant structures were modeled and their affinity with their known cofactor Guanosine-5'-triphosphate (GTP) was assessed which showed diverse binding energies ranged between (-7.436 to -6.950 kcal/mol) for the variants compared to wild-type (-7.428 kcal/mol). Finally, the molecular dynamics simulation of each variant was investigated which showed difference in trajectory between the pathogenic and non-pathogenic variant. Our analysis suggests change in amino acid residue of TUBB structure has notably affects the protein flexibility and their interactions with known cofactor. Overall, our findings provide insight on the relationship between TUBB variants and their structural dynamics that may cause diverse effects leading to cortical dysplasia.

Frustration analysis of TBK1 missense mutations reported in ALS/FTD and cancer patients

Tank-binding kinase 1 (TBK1) is a multifunctional kinase having essential roles in cellular processes, autophagy/mitophagy, and selective clearance of damaged proteins. More than 90 mutations in the TBK1 gene are linked with multiple cancer types, amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD). Some of these missense mutations disrupt the abilities of TBK1 to dimerize, associate with the mitophagy receptor optineurin (OPTN), autoactivate, or catalyze phosphorylation. Some mutations may cause severe dysregulation of the pathway, while others induce a limited disruption. Here, we have studied those mutations reported in cancer, ALS and FTD, and subsequently investigated the effect of missense mutations on the structure and function of TBK1 for localized residual frustration change. Out of 33 ALS/FTD causing mutations and 28 oncogenic mutations, 10 mutations and 12 oncogenic mutations showed significant change in the residual frustration. The local frustration plays an important role in the conformation of protein structure in active and inactive kinases. Our analysis reports the change in residual frustration state, conformational change and effect on active and inactive TBK1 function due to ALS/FTD causing and oncogenic missense mutations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03240-0.

Investigating the Mechanism of Inhibition of Cyclin-Dependent Kinase 6 Inhibitory Potential by Selonsertib: Newer Insights Into Drug Repurposing

Cyclin-dependent kinases (CDKs) play significant roles in numerous physiological, and are considered an attractive drug target for cancer, neurodegenerative, and inflammatory diseases. In the present study, we have aimed to investigate the binding affinity and inhibitory potential of selonsertib toward CDK6. Using the drug repurposing approach, we performed molecular docking of selonsertib with CDK6 and observed a significant binding affinity. To ascertain, we further performed essential dynamics analysis and free energy calculation, which suggested the formation of a stable selonsertib-CDK6 complex. The in-silico findings were further experimentally validated. The recombinant CDK6 was expressed, purified, and treated with selonsertib. The binding affinity of selonsertib to CDK6 was estimated by fluorescence binding studies and enzyme inhibition assay. The results indicated an appreciable binding of selonsertib against CDK6, which subsequently inhibits its activity with a commendable IC50 value (9.8 μM). We concluded that targeting CDK6 by selonsertib can be an efficient therapeutic approach to cancer and other CDK6-related diseases. These observations provide a promising opportunity to utilize selonsertib to address CDK6-related human pathologies.

Comparative analysis of web-based programs for single amino acid substitutions in proteins

Single amino-acid substitution in a protein affects its structure and function. These changes are the primary reasons for the advent of many complex diseases. Analyzing single point mutations in a protein is crucial to see their impact and to understand the disease mechanism. This has given many biophysical resources, including databases and web-based tools to explore the effects of mutations on the structure and function of human proteins. For a given mutation, each tool provides a score-based outcomes which indicate deleterious probability. In recent years, developments in existing programs and the introduction of new prediction algorithms have transformed the state-of-the-art protein mutation analysis. In this study, we have performed a systematic study of the most commonly used mutational analysis programs (10 sequence-based and 5 structure-based) to compare their prediction efficiency. We have carried out extensive mutational analyses using these tools for previously known pathogenic single point mutations of five different proteins. These analyses suggested that sequence-based tools, PolyPhen2, PROVEAN, and PMut, and structure-based web tool, mCSM have a better prediction accuracy. This study indicates that the employment of more than one program based on different approaches should significantly improve the prediction power of the available methods.

Impact of Single Amino Acid Substitutions in Parkinsonism-Associated Deglycase-PARK7 and Their Association with Parkinson’s Disease

Parkinsonism-associated deglycase-PARK7/DJ-1 (PARK7) is a multifunctional protein having significant roles in inflammatory and immune disorders and cell protection against oxidative stress. Mutations in PARK7 may result in the onset and progression of a few neurodegenerative disorders such as Parkinson’s disease. This study has analyzed the non-synonymous single nucleotide polymorphisms (nsSNPs) resulting in single amino acid substitutions in PARK7 to explore its disease-causing variants and their structural dysfunctions. Initially, we retrieved the mutational dataset of PARK7 from the Ensembl database and performed detailed analyses using sequence-based and structure-based approaches. The pathogenicity of the PARK7 was then performed to distinguish the destabilizing/deleterious variants. Aggregation propensity, noncovalent interactions, packing density, and solvent accessible surface area analyses were carried out on the selected pathogenic mutations. The SODA study suggested that mutations in PARK7 result in aggregation, inducing disordered helix and altering the strand propensity. The effect of mutations alters the number of hydrogen bonds and hydrophobic interactions in PARK7, as calculated from the Arpeggio server. The study indicated that the alteration in the hydrophobic contacts and frustration of the protein could alter the stability of the missense variants of the PARK7, which might result in disease progression. This study provides a detailed understanding of the destabilizing effects of single amino acid substitutions in PARK7.

Impact of Deleterious Mutations on Structure, Function and Stability of Serum/Glucocorticoid Regulated Kinase 1: A Gene to Diseases Correlation

Serum and glucocorticoid-regulated kinase 1 (SGK1) is a Ser/Thr protein kinase involved in regulating cell survival, growth, proliferation, and migration. Its elevated expression and dysfunction are reported in breast, prostate, hepatocellular, lung adenoma, and renal carcinomas. We have analyzed the SGK1 mutations to explore their impact at the sequence and structure level by utilizing state-of-the-art computational approaches. Several pathogenic and destabilizing mutations were identified based on their impact on SGK1 and analyzed in detail. Three amino acid substitutions, K127M, T256A, and Y298A, in the kinase domain of SGK1 were identified and incorporated structurally into original coordinates of SGK1 to explore their time evolution impact using all-atom molecular dynamic (MD) simulations for 200 ns. MD results indicate substantial conformational alterations in SGK1, thus its functional loss, particularly upon T256A mutation. This study provides meaningful insights into SGK1 dysfunction upon mutation, leading to disease progression, including cancer, and neurodegeneration.

Genomic Variations in the Structural Proteins of SARS-CoV-2 and Their Deleterious Impact on Pathogenesis: A Comparative Genomics Approach

A continual rise in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection causing coronavirus disease (COVID-19) has become a global threat. The main problem comes when SARS-CoV-2 gets mutated with the rising infection and becomes more lethal for humankind than ever. Mutations in the structural proteins of SARS-CoV-2, i.e., the spike surface glycoprotein (S), envelope (E), membrane (M) and nucleocapsid (N), and replication machinery enzymes, i.e., main protease (Mpro) and RNA-dependent RNA polymerase (RdRp) creating more complexities towards pathogenesis and the available COVID-19 therapeutic strategies. This study analyzes how a minimal variation in these enzymes, especially in S protein at the genomic/proteomic level, affects pathogenesis. The structural variations are discussed in light of the failure of small molecule development in COVID-19 therapeutic strategies. We have performed in-depth sequence- and structure-based analyses of these proteins to get deeper insights into the mechanism of pathogenesis, structure-function relationships, and development of modern therapeutic approaches. Structural and functional consequences of the selected mutations on these proteins and their association with SARS-CoV-2 virulency and human health are discussed in detail in the light of our comparative genomics analysis.