While the double helix is the most stable conformation of DNA inside cells, its transient unwinding and subsequent partial separation of the two complementary strands yields an intermediate single-stranded DNA (ssDNA). The ssDNA is involved in all major DNA transactions such as replication, transcription, recombination, and repair. The process of DNA unwinding and translocation is shouldered by helicases that transduce the chemical energy derived from nucleotide triphosphate (NTP) hydrolysis to mechanical energy and utilize it to destabilize hydrogen bonds between complementary base pairs.
View Article and Find Full Text PDFBrief Funct Genomics
January 2024
To survive and establish a niche for themselves, bacteria constantly evolve. Toward that, they not only insert point mutations and promote illegitimate recombinations within their genomes but also insert pieces of 'foreign' deoxyribonucleic acid, which are commonly referred to as 'genomic islands' (GEIs). The GEIs come in several forms, structures and types, often providing a fitness advantage to the harboring bacterium.
View Article and Find Full Text PDFHelicases are ATP-driven molecular machines that directionally remodel nucleic acid polymers in all three domains of life. They are responsible for resolving double-stranded DNA (dsDNA) into single-strands, which is essential for DNA replication, nucleotide excision repair, and homologous recombination. RecD2 from Deinococcus radiodurans (DrRecD2) has important contributions to the organism's unusually high tolerance to gamma radiation and hydrogen peroxide.
View Article and Find Full Text PDFIntegration Host Factor (IHF) is a heterodimeric site-specific nucleoid-associated protein (NAP), well known for its DNA bending ability. Although the IHF induced bending states of DNA have been captured by both X-ray Crystallography and Atomic Force Microscopy (AFM), the range of flexibility and degree of heterogeneity in terms of quantitative analysis of the nucleoprotein complex has largely remained unexplored. Binding of IHF leads to introduction of two kinks in the dsDNA that allowed us to come up with a quadrilateral model.
View Article and Find Full Text PDFTuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) has emerged in recent decades as one of the leading causes of mortality worldwide. The burden of TB is alarmingly high, with one third affected global population as reported by WHO. Short-course treatment with an antibiotic is a powerful weapon to treat infection of susceptible MTB strain, however; MTB has developed resistance to anti-TB drugs, which is an escalating global health crisis.
View Article and Find Full Text PDFActa Crystallogr D Struct Biol
June 2019
Several pathogenic bacteria utilize sialic acid, including host-derived N-acetylneuraminic acid (Neu5Ac), in at least two ways: they use it as a nutrient source and as a host-evasion strategy by coating themselves with Neu5Ac. Given the significant role of sialic acid in pathogenesis and host-gut colonization by various pathogenic bacteria, including Neisseria meningitidis, Haemophilus influenzae, Pasteurella multocida and Vibrio cholerae, several enzymes of the sialic acid catabolic, biosynthetic and incorporation pathways are considered to be potential drug targets. In this work, findings on the structural and functional characterization of CMP-N-acetylneuraminate synthetase (CMAS), a key enzyme in the incorporation pathway, from Vibrio cholerae are reported.
View Article and Find Full Text PDFEmergence of antimicrobial resistance mediated through New Delhi metallo-β-lactamases (NDMs) is a serious therapeutic challenge. Till date, 16 different NDMs have been described. In this study, we report the molecular and structural characteristics of NDM-5 isolated from an Escherichia coli isolate (KOEC3) of bovine origin.
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