BTISNet site

Objectives

Marine Cyanobacteria deposition and maintenance.
Promoting education and human resource development in Bioinformatics.
24 x 7 Internet connectivity with 512 kbpsfor researchers.

Current area of research

Comprehensive analysis of enzymes involved in cyanobacterial lipid pathway.
Identification, classification and evolution of cyanobacterial detoxification enzymes glutathione – S- transferases (GST)
Studying the binding affinity of xenobiotic compounds and glutathione- S-transferases.
Cyanobacterial stress associated enzymes and signaling pathways.
Comparative analysis of cyanobacterial CO2 fixing enyzmes in C3 & C4 pathways.
Omics studies.

Databases/applications developed

Complete datasheet of cyanobacterial cultures with GPS (Global Positioning System)value available in www.nfmc.res.in

A a database- Cyanobacterial Knowledge Bases

Achievments at glance

Molecular characterization of marine cyanobacteria

India is one of the major marine biodiversity “hotspots” of the world with a vast coastal area of @7700 km. The diverse organisms of “hotspots” should be conserved and catalogued for prosterity.Cyanobacteria, the unique group of oxygenic photoautotrophic prokaryotes possess extensive morphological diversity ranging from single celled, colonial to differentiated multicellular forms with branching patterns. Due to their wide diversity and adaptability,they could survive in varied marine ecological niches such as estuaries, coral reefs, mangroves, salt pans, backwaters, rocky shores and sandy shores. The cyanobacterial strains of various Indian coastal areas are catalogued and conserved for various biotechnological purposes in our repository.Traditionally, cyanobacteria are classified on the basis of morphological approach but certain morphological criteria used for classification have only ecotypic value which leads to misinterpretation of identification.Hence the identification has also to be carried out at the genetic level using molecular approach which offers the possibility to estimate the biodiversity upto species level. Precise identification of cyanobacterial strains in our germplasmand to optimize the accuracy of taxonomic identification is most vital. Since NFMC has a rich marine microalgal collection of @630 strains, we are concerned in the development of foolproof identification method for cyanobacterial taxa using 3 molecular markers such as 16S rRNA, 16-23S ITS region and cpc regions along with the traditional morphological method. Gene details sequenced so far were accessible in Gene sequencing portal of NFMC website (http://www.nfmc.res.in).

Comparative analysis of cyanobacterial superoxide dismutases, a canonical form

Superoxide dismutases (SOD) are ubiquitous metalloenzymes that catalyze the disproportion of superoxide to peroxide and molecular oxygen through alternate oxidation and reduction of their metal ions. In general, SODs are classified into four forms by their catalytic metals namely; FeSOD, MnSOD, Cu/ZnSOD and NiSOD. In addition, a cambialistic form that uses Fe/Mn in its active site also exists. Cyanobacteria, the oxygen evolving photosynthetic prokaryotes, produce reactive oxygen species that can damage cellular components leading to cell death. Thus, the co-evolution of an antioxidant system was necessary for the survival of photosynthetic organisms with SOD as the initial enzyme evolved to alleviate the toxic effect. Cyanobacteria represent the first oxygenic photoautotrophs and their SOD sequences available in the databases lack clear annotation.
Our in silico analysis on the sequence conservation and structural analysis of Fe (Thermosynechococcus elongatus BP1) and MnSOD (Anabaena sp. PCC7120) reveal the sharing of N and C terminal domains. At the C terminal domain, the metal binding motif in cyanoprokaryotes is DVWEHAYY while it is D-X-[WF]-E-H-[STA]-[FY]-[FY] in other pro- and eukaryotes. The cyanobacterial FeSOD differs from MnSOD at least in three ways viz.

FeSOD has a metal specific signature F184X3A188Q189.......T280......F/Y303
while, in Mn it is R184X3G188G189......G280......W303
Aspartate ligand forms a hydrogen bond from the active site with the outer sphere residue of W243 in Fe where as it is Q262 in MnSOD; and
Two unique lysine residues at positions 201 and 255 with a photosynthetic role, found only in FeSOD.

Further, most of the cyanobacterial Mn metalloforms have a specific transmembrane hydrophobic pocket that distinguishes FeSOD from Mn isoform. Cyanobacterial Cu/ZnSOD has a copper domain and two different signatures G-F-H-[ILV]-H-x-[NGT]-[GPDA]-[SQK]-C and G-[GA]-G-G-[AEG]-R-[FIL]-[AG]- C-G, while Ni isoform has an nickel containing SOD domain containing a Ni-hook HCDGPCVYDPA.
Our study or the first time have unraveled the ambiguity among cyanobacterial SOD isoforms. NiSOD is the only SOD found in lower forms; whereas, Fe and Mn occupy the higher orders of cyanobacteria. Cyanobacteria harbor either Ni alone or a combination of Fe and Ni or Fe and Mn as their catalytic active metal while Cu/Zn is rare and cambialistic form is absent. SOD is important, which produces OH radical and H2O2, which helps in decolourization of effluent. Thereby SOD is involved in killing pathogens in sewage.

a. The active site residues of Fe Superoxide dismutase of Thermosynechococcus elonagtus. (PDB: 1gv3); b. The active site residues of Mn Superoxide dismutase of Anabaena sp. ( PDB: 1my6)

Project titled “Over Expression of Engineered SOD Enzyme in Marine Cyanobacteria for Bioremediation Purposes”, sponsored byDBT, Govt. of India

Siderophore mediated uranium sequestration

Increasing contamination of the environment by uranium on account of its mining and disposal of tailings is a worldwide problem. Microbial interactions with metals form an important part of the natural biogeochemical processes and have important consequences for human society. It is therefore, vital to advance our understanding of the metal-microbe interactions that may include physical and chemical adsorption, ion exchange co ordination, complexation, chelation and micro-precipitation in order to develop suitable bioremediation strategies for metal contaminated sites. Among microbes, cyanobacteria represent a morphologically diverse group of oxygenic, gram-negative photosynthetic prokaryotes, which are widely distributed in freshwater, marine and terrestrial environments. These organisms respond and adapt to most stress conditions and are often abundant in metal contaminated environments. Siderophores, constitute a major class of naturally occurringchelators that includes hydroxamate, catecholate, and carboxylicacid functional groups secreted by microorganisms in various habitats,which bind to iron and mediate its transport to the cell. Thesemetal chaperones are majorly specific for iron. Inspite of its specification for iron complexation, marine cyanobacterium S.elongatus BDU130911 was evaluated for siderophore production and its specificity to complex with uranium through in vitro and in silico analysis. Wet lab studies corroborate the siderophore production in marine cyanobacterium S.elongatus BDU130911and were identifiedas hydroxamate type. Also hydroxamate siderophore complexation with uranium was estimated to be 50% by Chrome Azurol S modified assay. In order to substantiate wet lab analysis, in silicodocking was performed between Desferroxamine (a standard hydroxamate type) with Fe (III) and UO22+. Docking studies validates the hydroxamate siderophore to bind effectively with Fe (III) and UO22+and their binding affinity constant remains >2Aº. This finding was the first report in marine cyanobacteria to elucidate uranium siderophore complexation through in vitro and in silico analysis.

Desferroxamine – Fe(III)

Desferroxamine – UO22+

Project titled “Marine cyanobacteria – A potential candidate for uranium mining”,, sponsored by DAE, Govt. of India

Marine cyanobacterial carbon sequestration

Rapidly growing concern on global warming is attributed to the elevated CO2 in the atmosphere and has instigated the necessity to find an efficient way to mitigate carbon dioxide.Currently, CO2 can be sequestered by chemical, biological and geological methods. Biological carbon sequestration hasgained attention as it results in the production of biomass and energy. Cyanobacteria the oxy - phototrophs possess much higher growth rate and ability to fix CO2 while capturing the solar energy with much greater efficiency over the terrestrial plants. Having evolved at CO2 rich atmospheres, these organisms are plausible candidates for carbon sequestration. Eighteen organisms representing three different ordershave been screened from the National Facility for Marine Cyanobacteriafor their carbon dioxide tolerance. The selected plausible strain was grown with continuous flow of carbon dioxide at concentration near to flue gas. The major carbon fixing enzymes of C3 and C4 cycles are also being studied for their role in carbon fixation at higher concentration of CO2. In silicoanalysis of CO2 fixing enzymes Phosphoenol pyruvate carboxylase and Ribulose 1,5 bis phosphate carboxylase/oxygenase untangles the ambiguity among cyanobacteria which can be up-regulated for high CO2 fixing capabilities.Our current research throws light upon calcifying potentials of the cyanobacteria at continuous carbon dioxide in order to convert CO2to insoluable form as CaCO3

docking pose of PEPCase with its substrate phosphoenolpyruvate

Project titled “CO2 sequestration of marine cyanobacteria for multiple utilization potentials”, sponsored by DST, Govt. of India