Due to the substantial interest in developing transposon technology for gene delivery and gene therapy, the Sleeping Beauty (SB) transposon system, the most active transposon in the vertebrate species, has been extensively studied. The SB transposon system is composed of the transposon DNA and the transposase enzyme. During the DNA transposition, one necessary step is the assembly of the transpososome. The transpososome is held by protein-protein interactions, and the formation of the transposase dimer is required for this process. PAI subdomain of the SB transposase has been found to mediate protein-protein interactions between the transposase subunits, but the specific conditions for this interaction remain unclear. In our recent study, we experimentally confirmed that the H19Y mutation in the PAI subdomain increased the structural stability of the subdomain, which allows studying protein-protein interactions at biologically relevant experimental conditions. In this study, we use microscale thermophoresis (MST), NMR spectroscopy, and crosslinking techniques to investigate the oligomerization of the PAI-H19Y mutant.