Fig. 7: Genomic ssDNA regions can catalyze porphyrin metalation in vitro.

a Insertion of Zn²⁺ into mesoporphyrin IX (mPIX) catalyzed by candidate ssDNA regions of human or mouse gDNA. The plots represent the time course of the absorbance at 410 nm corresponding to the characteristic peak (Soret band) of Zn-mPIX (normalized by the porphyrin concentration). Spectra were captured every 30 min. Solid line: Zn²⁺+Pb²⁺, dashed line: Zn²⁺ only. Red: Bmpr1a (A,B), green: RPL7AP61 (C,D), blue: TATDN2P1 (E,F); native gDNA (G), denatured gDNA (H), denatured HaeIII cut gDNA (I); b Slopes of catalytic activity curves. Data are presented as mean ± SEM. Wilcoxon rank-sum test (two-sided). ns, not significant. ***, p < 0.001, 3 independent experiments; c Comparison of catalytic activity slopes for gDNAzyme w/ and w/o Pb²⁺ cofactor, and mouse genomic DNA. Data are presented as mean ± SEM. Wilcoxon rank-sum test (two-sided). ***, p < 0.001, n = 3 independent experiments; d Catalytic activity of TATDN2P1 DNAzyme in various conformations. Green: single-stranded short sequence, Orange: single-stranded long sequence, Red: long sequence constrained to form a short loop, Blue: long sequence constrained to form a long loop; Dark red: single-stranded short sequence but w/o Pb²⁺; e Mouse cortical neurons in primary cell culture interrogated with FRET-FISH. Black arrows point to the single-stranded DNA areas that contain sequences capable of acting catalytically from the Bmpr1a locus identified by FRET-FISH signal which are visualized with pseudo-colored red dots that are on the periphery of neuronal nucleus. Calibration bar = 20 μm.