Abstract The presence of a gene encoding small heat shock protein IbpA in Acholeplasma laidlawii (AlIbpA) appears to be one of the key factors determining the high adaptive capabilities of this mycoplasma. Previously, we showed a participation of the N-and C-terminal regions of AlIbpA in functions of chaperone in vitro. The aim of this work was to establish the involvement of the N - and C-terminal motifs of the recombinant AlIbpA in the survival of Escherichia coli cells under temperature stress in vivo. To determine this, we used genetically engineered versions of the AlIbpA with truncations and mutations in the N - and C-terminal domains. Viability was determined by counting CFU and differential fluorescent staining. Studies have shown that hyperproduction of the N-termini-modified IbpA from AlIbpA is able to exhibit thermotolerance E. coli cells. This research was funded by the Russian Science Foundation (project No. 17-74-20065), the microscopy assays were funded by RFBR (project № 20-34-90066).