Extended Data Fig. 4: Structure and sequence comparisons of the SPARTA complex with related proteins.
From: Target ssDNA activates the NADase activity of prokaryotic SPARTA immune system
(a) Structural comparison of the prokaryotic R. sphaeroides RsAgo complex (PDB 5AWH, in grey) and monomeric SPARTAgRNA-ssDNA complex (in color). (b) Multiple sequence alignment of the conserved catalytic tetrad motif in the PIWI domain of C. thermophila SPARTA, NP_036286.2 (Homo sapiens AGO2), WP_011011654.1 (Pyrococcus furiosus Argonaute) and WP_011174533.1 (Thermus thermophilus Argonaute). The catalytic motif DEDX is indicated with red font. (c) Structural comparison of the catalytic tetrad between T. thermophilus TtAgo (grey, PDB 3F73) and C. thermophila SPARTA (dark green). (d) Structural alignment of the R. sphaeroides RsAgo N domain, L1, L2 (PDB 5AWH) and C. thermophila SPARTA APAZ domain. (e) The C. thermophila SPARTA TIR domain (magenta) structurally resembles the H. sapiens MyD88 TIR domain (grey, PDB 7BEQ). (f) Ribbon representation of the SPARTA TIR domain. The conserved structural elements (αA–αE, βA–βE) and the BB loop critical for NADase activity are labeled.
