Fig. 5.

Effect of heat stress on peptidyl-prolyl cis-trans isomerase (PPIase) activity of the E. coli cells transformed with non-recombinant pET-28a(+) (vector control) and recombinant vector containing cDNAs encoding different variants of TaCypA-1. The cells were grown at 47 °C and harvested after 2 h, 3 h, and 5 h of induction with 0.5 mM of isopropyl β-d-1-thiogalactopyranoside. Total PPIase activity in the cell cultures was estimated by studying the effect of 10 μg of crude proteins, harvested from the induced E. coli cultures, on the chymotrypsin-mediated cleavage of the test peptide (N-succinyl-ala-ala-pro-phe-p-nitroanilidine). The PPIase activity is expressed as first order rate constant (s⁻¹). Data represent the mean ±S.E of three replicates. Asterisks represent level of significance by using Fisher's LSD method after two way analysis of variance of this data. * = Statistically significant at P < .05.