Investigation of F۴۲۰ protein structure in mycobacteria

Objective: The cofactor F۴۲۰, a unique deazaflavin molecule, plays a significant role in the redox metabolism of mycobacteria, including Mycobacterium tuberculosis (Mtb). F۴۲۰ is involved in a wide range of essential biochemical reactions, particularly in the metabolism of mycobacteria under stress conditions such as hypoxia and oxidative stress. These conditions are common in the granulomas that characterize tuberculosis infections, where Mtb is often exposed to fluctuating oxygen levels. The objective of this study was to elucidate the structural characteristics of F۴۲۰-dependent proteins in mycobacteria and to investigate their functional implications in redox homeostasis and antibiotic resistance. F۴۲۰ is integral to several key metabolic pathways in mycobacteria, such as methanogenesis and sulfate reduction, and it supports the action of enzymes involved in the reduction of substrates critical to the survival of Mtb. The critical involvement of F۴۲۰ in these metabolic pathways, especially during oxidative stress and the persistence of Mtb, suggests that a deeper understanding of its structure and function could offer valuable insights into new drug targets for tuberculosis (TB) treatment. Targeting F۴۲۰-dependent proteins could lead to novel therapeutic strategies, particularly to combat drug-resistant strains of Mtb, which remain a major global health challenge. Materials and Methods: This study employed a combination of bioinformatics and computational modeling techniques to analyze the structure of F۴۲۰-dependent enzymes. Sequence analysis was performed using phylogenetic profiling of F۴۲۰ biosynthetic genes across mycobacterial species. Three key F۴۲۰-dependent enzymes, including F۴۲۰-dependent glucose-۶-phosphate dehydrogenase (FGD), F۴۲۰H۲-dependent quinone reductase (Fqr), and F۴۲۰-dependent methylenetetrahydromethanopterin reductase (Mer), were selected for detailed structural analysis. Modeling of these proteins was done to determine their three-dimensional structure in atomic resolution. Molecular dynamics simulations were used to evaluate the stability and structural dynamics of enzyme-cofactor interactions. In addition, enzymatic assays were performed to evaluate the catalytic activity of F۴۲۰-dependent proteins under different redox conditions. Results: The phylogenetic analysis revealed a conserved distribution of F۴۲۰ biosynthetic genes across pathogenic mycobacteria, with notable variations in non-pathogenic strains. This suggests a functional divergence linked to pathogenicity, where pathogenic strains may rely more heavily on F۴۲۰ for key metabolic functions that are critical for their survival and virulence. The crystal structures of FGD, Fqr, and Mer were resolved at high resolutions of ۱.۸ Å, ۲.۱ Å, and ۱.۹ Å, respectively, providing detailed insights into enzyme-cofactor interactions and allowing for a deeper understanding of the molecular mechanisms involved. Structural analysis showed that F۴۲۰ binds within a distinct pocket, stabilized by a network of hydrogen bonds and hydrophobic interactions, underscoring its specificity for target enzymes. The active site residues involved in F۴۲۰ binding were identified as Ser۹۴, Thr۱۵۸, and Glu۲۰۳ in FGD, which are highly conserved across species, further supporting the cofactor’s critical role in the enzymatic process. Molecular dynamics simulations indicated that the F۴۲۰-cofactor complex is exceptionally stable, with minimal fluctuations in the protein backbone, facilitating efficient hydride transfer during catalysis. Enzymatic assays revealed that the presence of F۴۲۰ led to a ۳.۵-fold increase in the catalytic activity of FGD, highlighting the cofactor’s essential role in enhancing enzyme function and its potential in metabolic processes crucial for mycobacterial survival, especially in challenging environments. Conclusion: This study offers a detailed structural and functional characterization of F۴۲۰-dependent enzymes in mycobacteria, highlighting the essential role of the F۴۲۰ cofactor in supporting redox reactions. These reactions are pivotal for the survival of mycobacteria, especially Mycobacterium tuberculosis (Mtb), under a variety of stress conditions, such as those encountered during infection. F۴۲۰’s involvement in crucial metabolic pathways, including those related to energy production and antioxidant defense, contributes to the

کلیدواژه ها:

F۴۲۰ protein structure ، mycobacteria ، redox metabolism ، Mycobacterium tuberculosis ، biochemical reactions ، metabolic pathways ، antibiotic resistance ، bioinformatics ، computational modeling ، phylogenetic analysis ، enzyme-cofactor interactions ، molecular dynamics simulations ، catalytic activity ، pathogenic mycobacteria ، crystal structures ، hydrogen bonds ، enzyme function ، metabolic processes ، tuberculosis treatment