Fig. 3: Structure comparison of BPSL1038 and CRISPR Cas2-associated proteins.

a Superimposition of BPSL1038 with Bha_Cas2, Spy_Cas2 and Xal_Cas2 with known DNase activity that cleaves double-stranded DNA (dsDNA). b Superimposition of BPSL1038 with Sso_Cas2 that is known to cleave single-stranded RNA (ssRNA). c Superimposition of BPSL1038 with Tth_Cas2 that is known to cleave dsDNA and ssRNA. d Superimposition of BPSL1038 with Hpy_VapD that is known to cleave mRNA. The β1-α1 and α2-β4 loops that were proposed as DNA and RNA recognition loops, respectively, are shorter in BPSL1038. Hpy_VapD has a helix formed in those respective loop regions which are not found in BPSL1038 and other Cas2 proteins. The catalytic active aspartate residue pairs are shown in stick format. e 2D topology diagram of BPSL1038, Bha_Cas2, Sso_Cas2, Tth_Cas2 and Hpy_VapS monomer generated using PDBsum⁶⁴.