Research Interests
Functional Proteonomics:
Our research is directed to study structure/function relationship of the complex metalloenzyme nitrogenase and generate a functional nitrogenase using minimal genetic information by reverse genetics. Our efforts are also focused on elucidating the roles of some of the nif-accessary proteins in the maturation and assembly of the nitrogenase.
Shown on right:
The structure of the MoFe protein and the NifD-K fusion protein as visualized in RasMol program. (A) shows the wild type MoFe protein. One alpha and beta subunit is shown as the ribbon diagram and the other alpha and beta subunit is shown as the line diagram. The and subunits are labeled. The location of the Ala-481 residue at the C terminus of the subunit and the location of the Pro-13 residue at the N terminus of the subunit are marked by arrows. (B) shows the NifD-K fusion protein. The residues joining the Ala-481 of the subunit with the Pro-13 of the subunit are shown by the arrow, and the newly inserted residues in the NifD-K fusion protein are listed.
(Suh, M. H., Pulakat, L., and Gavini, N. (2003) Journal of Biological Chemistry 278, 5353-5360)
Bacterial Genomics:
We are involved in the genome project of Azotobacter vinelandii. Currently the genome is assembled in 91 contigs and contains 6147 candidate protein-encoding ORFs. We are currently involved in annotation of the genome in collaboration with Azotobacter research community. We are also studying the correlation of codon usage and expression levels of various genes in a-proteobacterial genomes in general and specifically in Azotobacter vinelandii.Studies utilizing several physical, biochemical and spectroscopic methods have suggested that A. vinelandii contains multiple copies (40-80 copies) of its chromosome per cell, whereas genetic analysis indicated that these cells function like haploid cells. To further verify if A. vinelandii indeed contains 40-80 copies of its chromosome per cell, we have developed an "In vivo chromosome counting" technique. The basic principle of this technique is to introduce the same genetic marker on the chromosome and on an extrachromosomal element of known copy number into the bacterium. The copy number of the chromosome can be determined by comparing the intensity of the hybridization signal generated by the DNA fragment carrying the chromosomal marker with that of the extrachromosomal marker when the total DNA isolated from this strain is hybridized with a probe made of the same genetic marker DNA. We believe that this "In vivo chromosome counting" technique can be used for determination of the copy number of the chromosome in other cells with appropriate modifications in the nature of the extrachromosomal element and the genetic marker.
Breast Cancer Gene Expression Profiles and Drug Development:
In our attempt to look for alternative methods for cancer therapy, we have come across a treatment in the Indian traditional medicine designated Ayurveda, using extracts from specific plants. However, no scientific analysis of how these extracts exert their beneficial effects has been carried out and there is no organized data to support the claims of efficacy of these extracts in cancer treatment. The lack of this information prevents the use of this potentially powerful anti-cancer agent in cancer therapy in the Western world. Therefore, we undertook research to examine the effects of these extracts on mouse and human cancer cells. We found that treatment with these extracts arrested the growth of mouse melanoma cells and human breast cancer cells. Further analysis on changes in gene expression profile of mouse melanoma cells using microarray showed specific decrease in the expression of several growth and metastasis promoting genes and increase in the expression of growth-inhibitory genes. The specific aim of this research is to characterize how these extracts affect tumor progression and gene expression profile in melanoma using mouse model.
Home