Fig. 5: Analysis of the TIR active site.
From: Nucleic acid mediated activation of a short prokaryotic Argonaute immune system
a Details of interactions between TIRA and TIRB (BE interface). The residues from BB-loop of TIRB forms extensive electrostatic interactions with residues from βD, βE and αE of TIRA. b Comparison of the NADase activity of TIR and pAgo mutants with wild-type SPARTA. TIR-Trp46 and TIR-Tyr105 are catalytic residues of SPARTA which are structurally conserved in AbTir and SARM1. Arg114 and Asn116 are involved at TIRA-TIRB interface. Gln35 and Tyr37 are involved at the pAgo-pAgo interface. The mutation of these residues results in a major reduction in the NADase activity. Data are presented as mean values +/- SD from experiments performed in triplicates. Source data are provided as a Source Data file. c Close-up view of the SPARTA active site formed across the TIRA and TIRB heterodimers is compared with that in AbTir (PDB:7UXU) and SARM1 (PDB: 7NAK). AbTir and SARM1 are depicted with bound NAD+ analogue (3AD).
