One central question surrounding the biosynthesis of fatty acids and polyketide-derived natural products is how the 4'-phosphopantetheinyl transferase (PPTase) interrogates the essential acyl carrier protein (ACP) domain to fulfill the initial activation step. The triggering factor of this study was the lack of structural information on PPTases at physiological pH, which could bias our comprehension of the mechanism of action of these important enzymes. Structural and functional studies on the family II PPTase PptAb of Mycobacterium abscessus show that pH has a profound effect on the coordination of metal ions and on the conformation of endogenously bound coenzyme A (CoA). The observed conformational flexibility of CoA at physiological pH is accompanied by a disordered 4'-phosphopantetheine (Ppant) moiety. Finally, structural and dynamical information on an isolated mycobacterial ACP domain, in its apo form and in complex with the activator PptAb, suggests an alternate mechanism for the post-translational modification of modular megasynthases.
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http://dx.doi.org/10.1111/febs.15273 | DOI Listing |
Malar J
January 2025
Department of Pharmacology, Kangwon National University School of Medicine, Chuncheon, 24341, Republic of Korea.
Background: The Plasmodium proteasome emerges as a promising target for anti-malarial drug development due to its potential activity against multiple life cycle stages.
Methods: In this investigation, a comparative analysis was conducted on the structural features of the β5 subunit in the 20S proteasomes of both Plasmodium and humans.
Results: The findings underscore the structural diversity inherent in both proteasomes.
Nat Commun
January 2025
Department of Biological Sciences, Purdue University, West Lafayette, 47907, Indiana, USA.
RNA plays a crucial role not only in information transfer as messenger RNA during gene expression but also in various biological functions as non-coding RNAs. Understanding mechanical mechanisms of function needs tertiary structure information; however, experimental determination of three-dimensional RNA structures is costly and time-consuming, leading to a substantial gap between RNA sequence and structural data. To address this challenge, we developed NuFold, a novel computational approach that leverages state-of-the-art deep learning architecture to accurately predict RNA tertiary structures.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Biochemistry, Memorial University of Newfoundland, 45 Arctic Avenue, St. John's, Newfoundland and Labrador, Canada. Electronic address:
d-ribose is a critical sugar substrate involved in the biosynthesis of nucleotides, amino acids, and cofactors, with its phosphorylation to ribose-5-phosphate by ribokinase (RK) constituting the initial step in its metabolism. RK is conserved across all domains of life, and its activity is significantly enhanced by monovalent metal (M) ions, particularly K, although the precise mechanism of this activation remains unclear. In this study, we present several crystal structures of human RK in both unliganded and substrate-bound states, offering detailed insights into its substrate binding process, reaction mechanism, and conformational changes throughout the catalytic cycle.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland.
For use in prevention and treatment, HIV-1 broadly neutralizing antibodies (bnAbs) have to overcome Env conformational heterogeneity of viral quasispecies and neutralize with constant high potency. Comparative analysis of neutralization data from the CATNAP database revealed a nuanced relationship between bnAb activity and Env conformational flexibility, with substantial epitope-specific variation of bnAb potency ranging from increased to decreased activity against open, neutralization-sensitive Env. To systematically investigate the impact of variability in Env conformation on bnAb potency we screened 126 JR-CSF point mutants for generalized neutralization sensitivity to weakly neutralizing antibodies (weak-nAbs) depending on trimer opening and plasma from people with chronic HIV-1 infection.
View Article and Find Full Text PDFChem Biodivers
January 2025
St Xavier's College, Kolkata, Department of Chemistry, 30, Mother teresa Sarani, Kol-16, 700016, Kolkata, INDIA.
Amino-quinolines are potential candidates that may provide some insight into the current chemotherapeutic research due to their demonstrated anti-cancer activity. This led us to synthesize and explore a new amino-azo-quinoline ligand H2L 1 and its square planar nickel(II) complexes [Ni(HL)(OAc)], 2 and [Ni(HL)Cl], 3 and the structures were determined by SCXRD. Theoretical investigation of redox orbitals of the complexes discloses that the reduction process is due to ligand reduction whereas both metal and ligand are contributing towards oxidation.
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