Functional analysis of metalloenzymes from human gut microbiota and their role in ulcerative colitis.

AIM: Metalloenzymes produced by gut microbiota play an essential role in various physiological processes, and maintains homeostasis of gastrointestinal tract. Our study includes functional analysis of microbial metalloenzymes using metagenomics and metatranscriptomics data from Inflammatory Bowel Disease Multiomics Database. METHODS AND RESULTS: The distance matrix calculated by using metalloenzymes data produced significant results for bacterial taxonomy, with higher variance compared to HMP analysis in both Western and Indian population. Differential gene expression analysis revealed altered expression of ulcerative colitis (UC)-associated enzymes, increased folds changes in Prevotella and Megamonas transcripts; whereas, low transcripts of Alistipes genera. Further, docking and simulation studies performed on screened UC-associated enzymes revealed changes in catalytic efficiency and ligand interacting residues. CONCLUSION: The ß-diversity using microbes containing metalloenzymes suggests considering small group of specific genes or enzymes for understanding the diversity between UC and healthy individuals. The docking and differential gene expression analysis collectively indicate the probable role of metalloenzymes and few UC-associated enzymes in the severity of UC.

Gut microbial metalloproteins and its role in xenobiotics degradation and ROS scavenging.

The gut microbial metalloenzymes play an important role in maintaining the balance between gut microbial ecosystem, human physiologically processes and immune system. The metals coordinated into active site contribute in various detoxification and defense strategies to avoid unfavourable environment and ensure bacterial survival in human gut. Metallo-ß-lactamase is a potent degrader of antibiotics present in periplasmic space of both commensals and pathogenic bacteria. The resistance to anti-microbial agents developed in this enzyme is one of the global threats for human health. The organophosphorus eliminator, organophosphorus hydrolases have evolved over a course of time to hydrolyze toxic organophosphorus compounds and decrease its effect on human health. Further, the redox stress responders namely superoxide dismutase and catalase are key metalloenzymes in reducing both endogenous and exogenous oxidative stress. They hold a great importance for pathogens as they contribute in pathogenesis in human gut along with reduction of oxidative stress. The in-silico study on these enzymes reveals the importance of point mutation for the evolution of these enzymes in order to enhance their enzyme activity and stability. Various mutation studies were conducted to investigate the catalytic activity of these enzymes. By using the "directed evolution" method, the enzymes involved in detoxification and defense system can be engineered to produce new variants with enhance catalytic features, which may be used to predict the severity due to multi-drug resistance and degradation pattern of organophosphorus compounds in human gut.

Metal manipulators and regulators in human pathogens: A comprehensive review on microbial redox copper metalloenzymes "multicopper oxidases and superoxide dismutases".

The chemistry of metal ions with human pathogens is essential for their survival, energy generation, redox signaling, and niche dominance. To regulate and manipulate the metal ions, various enzymes and metal chelators are present in pathogenic bacteria. Metalloenzymes incorporate transition metal such as iron, zinc, cobalt, and copper in their reaction centers to perform essential metabolic functions; however, iron and copper have gained more importance. Multicopper oxidases have the ability to perform redox reaction on phenolic substrates with the help of copper ions. They have been reported from Enterobacteriaceae, namely Salmonella enterica, Escherichia coli, and Yersinia enterocolitica, but their role in virulence is still poorly understood. Similarly, superoxide dismutases participate in reducing oxidative stress and allow the survival of pathogens. Their role in virulence and survival is well established in Salmonella typhimurium and Mycobacterium tuberculosis. Further, to ensure survival against stress, like metal starvation or metal toxicity, redox metalloenzymes and metal transportation systems of pathogens actively participate in metal homeostasis. Recently, the omics and protein structure biology studies have helped to predict new targets for regulation the colonization potential of the pathogenic strains. The current review is focused on the major roles of redox metalloenzymes, especially MCOs and SODs of human pathogenic bacteria.