The evolution of CRISPR-Cas systems and their possible origin from mobile genetic elements of transposons are currently being actively studied. Recently, unique systems have been discovered in a new group of Asgardarchaea that presumably function as transposons and contain Cas1-like proteins. In this study, the genetic and biochemical technologies were used, along with electrophoresis, affinity chromatography, and high-resolution mass spectrometry, to obtain and partially characterize a recombinant version of one of these proteins, Cas1_3. In particular, it was shown to have the ATPase activity, the quantitative value of the latter being determined by the spectrophotometric method. The results obtained may be useful in understanding the mechanisms of functioning the potential ancestor of CRISPR-Cas systems.