Exposure to thermal stress induces overexpression of protein-L-iso aspartate-O-methyl transferase (PIMT) in Pseudomonas aeruginosa.

BACKGROUND AND OBJECTIVES: Apart from spontaneous deamidation and isomerization of Asp/Asn residues, factors like ageing, oxidative stress, salinity and heat stress may also form abnormal isoaspartate (iso-Asp) residues compromising protein structure and function. PIMT helps in restoration of such iso-Asp residues. Pseudomonas aeruginosa is a gram-negative bacteria responsible for diseases with varied degree of pathogenesis in humans and animals. They can survive a wide range of temperature between 25°C to 42°C. The objective of the current study was to monitor the expression dynamics of PIMT in Pseudomonas aeruginosa upon exposure to different thermal stresses. MATERIALS AND METHODS: The mid log phase culture of Pseudomonas aeruginosa was exposed to different temperature (37°C, 42°C, 56°C, 80°C) for an hour. The expression levels of PIMT were quantified by Western blot and ELISA. RESULTS: A relatively higher level of expression of PIMT was observed in the group exposed to 42°C, 56°C, 80°C in comparison to 37°C. The expression of PIMT increased around 1.5 times in the group exposed to 42°C. CONCLUSION: A temperature dependent overexpression of PIMT was observed in Pseudomonas aeruginosa.