The scientific contribution of Dr. Dipankar Chatterji can be broadly classified under two headings:
a. Structural basis for nucleic acid-protein recognition
b. Regulation of gene expression in prokaryotes.
Prof. Chatterji joined MBU during 1999 after a stint at CCMB, Hyderabad. At CCMB, he started working on transcription mechanism in E. coli and demonstrated the orientation of substrates at the catalytic site of RNA polymerase by FRET analysis. During this period he also looked at the binding site of the inhibitor rifampicin on RNA polymerase. Subsequently, the group showed the mechanism of sigma factor recognition by core RNA polymerase and the role of DNA binding domain of sigma factor. At Hyderabad, they demonstrated that the stringent factor ppGpp regulates gene expression by directly interacting with RNA polymerase during nutritional starvation. Upon joining MBU, he started a major initiative on mycobacterial transcription with special emphasis on stress induced regulation of gene expression during starvation. They first established stringency in mycobacteria, discovered the mechanism of stringent response in a Gram positive organism and generated a strain of M. smegmatis which is devoid of ppGpp synthesizing enzyme. The proximate aim was to characterize the survival and behavior of such a mutated organism. During this period, they identified a new stress induced protein DPS, structurally characterized it by X-ray crystallography and proposed its role in DNA compaction in bacterial population during starvation. Prof. Chatterji's current interest includes the role of omega factor in bacterial transcription. They have shown earlier that omega subunit of RNA polymerase folds and assembles RNA polymerase during multi-step assembly process, however, its function during the catalytic process was not known. His group now has proposed that there is plasticity in the catalytic centre of RNA polymerase and the interface involving omega plays a major role therein. This group has spent considerable time to set up an assay to follow macromolecular interaction in a crowded environment and carried out RNA polymerase assembly as well as promoter-enzyme interaction by Langmuir-Blodgett technique. In recent times, they have initiated a new project on quorum sensing in mycobacteria and its relationship with stress. Prof. Chatterji is now utilizing the dodecameric DPS protein as a vehicle for nano-delivery of ligands.