Biology subjects

Badmalia, M. D.

Publications and source records attributed to Badmalia, M. D..

2 recordsLinked to original sources

bioRxiv2021

Identification and characterization of a G-quadruplex structure in the pre-core promoter region of hepatitis B virus

Worldwide, [~]250 million people are chronically infected with the hepatitis B virus (HBV) and are at increased risk of cirrhosis and hepatocellular carcinoma. The HBV persists as covalently closed circular DNA (cccDNA), which acts as the template for all HBV mRNA transcripts. Nucleos(t)ide analogs do not directly target the HBV cccDNA and cannot eradicate the HBV. We have discovered a unique structural motif, a G-quadruplex in HBVs pre-core promoter region that is conserved amongst nearly all genotypes, and is central to critical steps in the viral life-cycle including the production of pre-genomic RNA, core and polymerase proteins, and encapsidation. Thus, an increased understanding of the HBV pre-core may lead to the development of novel anti-HBV cccDNA targets. We utilized biophysical methods to characterize the presence of the G-quadruplex, employed assays using a known quadruplex- binding protein (DHX36) to pull-down HBV cccDNA, and compared HBV infection in HepG2 cells transfected with wild-type and mutant HBV plasmids. This study provides insights into the presence of a G-quadruplex in the HBV pre-core promoter region essential for HBV replication. The evaluation of this critical host-protein interaction site in the HBV cccDNA may ultimately facilitate the development of novel anti-HBV therapeutics against the resilient cccDNA template.

biophysics↗

bioRxiv2020

Bioinformatic Analysis of Structure and Function of Lim Domains of Zyxin Family of Proteins

Members of the human Zyxin family are LIM domain-containing proteins that perform critical cellular functions and are indispensable for cellular integrity. Despite their importance, not much is known about their structure, functions, interactions and dynamics. To provide insights into these, we used a set of in-silico tools and databases and analyzed their amino acid sequence, phylogeny, post-translational modifications, structure-dynamics, molecular interactions, and functions. Our analysis revealed that zyxin members are ohnologs. Presence of a conserved nuclear export signal composed of LxxLxL/LxxxLxL consensus sequence, as well as a possible nuclear localization signal, suggesting that Zyxin family members may have nuclear and cytoplasmic roles. The molecular modeling and structural analysis indicated that Zyxin family LIM domains share similarities with transcriptional regulators and have positively charged electrostatic patches, which may indicate that they have previously unanticipated nucleic acid binding properties. Intrinsic dynamics analysis of Lim domains suggest that only Lim1 has similar internal dynamics properties, unlike Lim2/3. Furthermore, we analyzed protein expression and mutational frequency in various malignancies, as well as mapped protein-protein interaction networks they are involved in. Overall, our comprehensive bioinformatic analysis suggests that these proteins may play important roles in mediating protein-protein and protein-nucleic acid interactions.

biochemistry↗