C. S. Raman

The primary objective of this project was to uncover previously unknown modes by which living organisms harvested energy. Specifically, it queried microbial systems, which were once thought to not be able to utilize oxygen. Through the use of cutting-edge approaches, we were able to identify novel mechanistic processes that allow organisms to thrive under varying environmental conditions. This constitutes a paradigm shift in the field. Our work has opened new vistas for expanding the horizons of energy conservation in biological systems, as well as shed light on green energy innovations.

The reversible two-electron interconversion of formate and CO ₂ is catalyzed by both non-metallo and metallo-formate dehydrogenases (FDHs). The latter group comprises molybdenum-or tungsten-containing enzymes with the metal coordinated by two equivalents of a pyranopterin cofactor, a cysteinyl or selenocysteinyl ligand supplied by the polypeptide, and a catalytically essential terminal sulfido ligand. In addition, these biocatalysts incorporate one or more [4Fe-4S] clusters for facilitating long-distance electron transfer. But an interesting dichotomy arises when attempting to understand how the metallo-FDHs react with O ₂ . Whereas existing scholarship portrays these enzymes as being unable to perform in air due to extreme O ₂ lability of their metal centers, studies dating as far back as the 1930s emphasize that some of these systems exhibit formate oxidase (FOX) activity, coupling formate oxidation to O ₂ reduction. Therefore, to reconcile these conflicting views, we explored context-dependent functional linkages between metallo-FDHs and their cognate electron acceptors within the same organism vis-à-vis catalysis under atmospheric conditions. Here, we report the discovery and characterization of an O ₂ -insensitive FDH2 from the sulfate-reducing bacterium Desulfovibiro vulgaris Hildenborough that ligates tungsten, selenocysteine, and four [4Fe-4S] clusters. Notably, we advance a robust expression platform for its recombinant production, eliminating both the requirement of nitrate or azide during purification and reductive activation with thiols and/or formate prior to catalysis. Because the distinctive spectral signatures of formate-reduced DvH-FDH2 remain invariant under anaerobic and aerobic conditions, we benchmarked the enzyme activity in air, identifying CO ₂ as the bona fide product of catalysis. Full reaction progress curve analysis uncovers a high catalytic efficiency when probed with an artificial electron acceptor pair. Furthermore, we show that DvH-FDH2 enables hydrogen peroxide production sans superoxide release to achieve O ₂ insensitivity. Direct electron transfer to cytochrome c in air also reveals that electron bifurcation is operational in this system. Taken together, our work unambiguously proves for the first time the coexistence of redox bifurcated FDH and FOX activities within a metallo-FDH scaffold. These findings have important implications for engineering O ₂ -tolerant FDHs and bio-inspired artificial metallocatalysts, as well as for the development of authentic formate/air biofuel cells, modulation of catalytic bias, assessing the limits of reversible catalysis, understanding directional electron transfer, and discerning formate bioenergetics of gut microbiota.

Most of the students of Engineering colleges in Vidarbha region select their employment through campus placements. It is thus the responsibility of the colleges to make the students skilled to enhance the chances of their employability. The paper divided the skill sets into and Social skillsand measured its impact on Employability Test Scores viz. Aptitude Test Score, Group Discussion Score and Personal Interview Score. It is found that social skills viz. Industry Institute Interaction and Leadership Quality of the students play an important role in deciding Employability Test Scores of the students. The results were arrived at by taking the sample 629 students of engineering colleges of Nagpur region. Hence the mapping of various parameters in their past social skill superimposed with current assessment of their potential on the basis of aptitude test, group discussion and personal interview can generate certain indicators of success in future placement/ higher education/ entrepreneurship in engineering profession.

Soluble guanylate cyclase (sGC) is the mammalian endogenous nitric oxide (NO) receptor that synthesizes cGMP upon NO activation. In synergy with the artificial allosteric effector BAY 41-2272 (a lead compound for drug design in cardiovascular treatment), sGC can also be activated by carbon monoxide (CO), but the structural basis for this synergistic effect are unknown. We recorded in the unusually broad time range from 1 ps to 1 s the dynamics of the interaction of CO binding to full length sGC, to the isolated sGC heme domain β₁(200) and to the homologous bacterial NO-sensor from Clostridium botulinum. By identifying all phases of CO binding in this full time range and characterizing how these phases are modified by BAY 41-2272, we show that this activator induces the same structural changes in both proteins. This result demonstrates that the BAY 41-2272 binding site resides in the β₁(200) sGC heme domain and is the same in sGC and in the NO-sensor from Clostridium botulinum.