Abstract Detail

Stress Tolerance

Kapoor, Shivali [1], Tripathi, S.N. [1], Shrivastava, Alpana [1].

Adaptive strategies, purification and sequence analysis of a thermostable catalase from a desiccation tolerant cyanobacterium Lyngbya arboricola.

A very upcoming and challenging issue in cell biology is the knowledge of mechanisms of drying and storing cells and keeping them structurally and functionally integrated for long periods. Also the utilization of understanding the mechanisms necessary for desiccation tolerance holds a promising tool in the future for the metabolic engineering of desiccation sensitive cells, mass production of additives (trehalose, sucrose, sorbitol, etc.), biosensors, in long term space travel, developing synthetic seed technologies, encapsulation technologies that rely on polymer mass transfer characteristics, in making and transportation of dry vaccines/drugs/proteins more widely available throughout the developing world where refrigeration, electricity, proper storage are less accessible. Thus various terrestrial cyanobacteria inhabiting buildings, rocks, trees such as Lyngbya, Tolypothrix, Gleocapsa, Scytonema,Nostoc having marked capacity for desiccation tolerance, have been known for years to survive extremes of matric water stresses. Our studies reflected presence of highly stable antioxidative enzymes in desiccation tolerant cyanobacteria and investigations were carried out by employing purified antioxidative enzymes at homogeneity levels to elucidate the mechanisms behind their stability. Catalases are known to retain its stability for longer duration, being active in freeze-dried permafrost samples (Gilichinsky et al. 1992) over a long period of millions years. Presence of stable and active catalase in cells of this desiccation tolerant terrestrial cyanobacterium Lyngbya arboricolastored in desiccated state for two years is not only reflective of the ability of the cyanobacterium to maintain structural and functional integrity of their macromolecules including proteins under extremes of desiccation, but also signifies for better availability of stable catalase in dry mats of this cyanobacterium. The present study reports for the first time the purification and characterization of a novel heterotetrameric catalase from Lyngbya arboricola which may also serve as a potential source for thermophilic industrial catalases. Phylogenetic, genotypic, and chemotypic analysis revealed that this catalase belonged to the clade 2 catalase exhibiting unusual resistances to physical and chemical denaturation. Comparative aminoacid sequence analysis with other thermophiles demonstrated that catalase isolated from Lyngbya arboricola showed a higher hydrophobicity, pI, positively charged residues, gravy value, kinetic efficiency, pH & temperature tolerance and an instability index greater than 40 than most of the thermophiles. Further study of the structural and functional characteristics of this enzyme gave us a greater insight into the possible mechanisms of its stability which would allow exploitation of its survival strategies for its biotechnological potential.

Broader Impacts:

1 - Banaras Hindu University, Department of Botany, Varanasi, UP, 221005, India

Keywords:
desiccation tolerance 
Antioxidative enzyme
stable catalase
Lyngbya arboricola
thermophilic.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM
Number: PST002
Abstract ID:818