Executive Summary : | The present proposal is aimed at biomimetic study of di-heme enzymes such as bCcP, MauG, and RoxA in order to understand the structure-function relationships at the molecular level. Di-heme enzymes are not simple heme assemblies but sophisticated devices. Each heme unit behaves like a domain in multi-domain proteins and also has specific functions, including a regulatory one. The functional significance of these heme structural arrangements is yet to be understood. Additionally, changing the bridging architectures would provide the role of bridge in the electronic communication. The enzymatic reaction mechanism would be elucidated by means of active site analogs; stabilizations of reactive intermediates etc. and information obtained will be useful to understand Nature’s sophisticated design to develop highly efficient catalyst. It is expected that the cooperative interaction between two heme centers will excel the activity incredibly. The axial ligands play an important role in defining the reaction type and enzymatic functionality by tuning the heme redox properties and thereby control the catalytic cycle. Several intriguing questions have puzzled the scientific community since the discovery of the bis-Fe(IV) intermediate, which, despite being a potent oxidant, displays extraordinary stability with a half-life of several minutes. Lessons obtained from biomimetic study will be helpful in designing/tuning better and efficient catalyst. The research will utilize a wide range of spectroscopic, theoretical, and chemical techniques to probe structure-function relationships to gain mechanistic insight, and also to address fundamental questions of relevance to chemistry and biology. The progress of the reaction and the electronic structures in solution will be monitored in situ by the application of UV-vis-NIR, NMR, Mossbauer, resonance Raman, magnetic and EPR spectroscopy, while DFT would be helpful for better understanding of the structure and property. |