PDF(Pubmed)
Abstract：
Recent discoveries establish DNA and RNA as bona fide substrates for ADP-ribosylation. NADAR (\"NAD- and ADP-ribose\"-associated) enzymes reverse guanine ADP-ribosylation and serve as antitoxins in the DarT-NADAR operon. Although NADARs are widespread across prokaryotes, eukaryotes, and viruses, their specificity and broader physiological roles remain poorly understood. Using phylogenetic and biochemical analyses, we further explore de-ADP-ribosylation activity and antitoxin functions of NADAR domains. We demonstrate that different subfamilies of NADAR proteins from representative E. coli strains and an E. coli-infecting phage retain biochemical activity while displaying specificity in providing protection from toxic guanine ADP-ribosylation in cells. Furthermore, we identify a myxobacterial enzyme within the YbiA subfamily that functions as an antitoxin for its associated DarT-unrelated ART toxin, which we termed YarT, thus presenting a hitherto uncharacterised ART-YbiA toxin-antitoxin pair. Our studies contribute to the burgeoning field of DNA ADP-ribosylation, supporting its physiological relevance within and beyond bacterial toxin-antitoxin systems. Notably, the specificity and confinement of NADARs to non-mammals infer their potential as highly specific targets for antimicrobial drugs with minimal off-target effects.
摘要：
最近的发现确立了DNA和RNA作为ADP-核糖基化的真正底物。NADAR(“NAD-和ADP-核糖”相关)酶逆转鸟嘌呤ADP-核糖基化并在DarT-NADAR操纵子中充当抗毒素。尽管NADAR在原核生物中普遍存在，真核生物,和病毒，它们的特异性和更广泛的生理作用仍然知之甚少。利用系统发育和生化分析，我们进一步探讨了NADAR结构域的去ADP核糖基化活性和抗毒素功能。我们证明了来自代表性大肠杆菌菌株和大肠杆菌感染噬菌体的NADAR蛋白的不同亚家族保留了生化活性,同时在提供保护免受细胞中毒性鸟嘌呤ADP-核糖基化方面表现出特异性。此外，我们确定了YbiA亚家族中的一种粘细菌酶，该酶可作为其相关的DarT无关ART毒素的抗毒素，我们称之为YarT，因此提供了迄今为止未表征的ART-YbiA毒素-抗毒素对。我们的研究有助于DNAADP核糖基化的新兴领域，支持其在细菌毒素-抗毒素系统内外的生理相关性。值得注意的是,NADARs的特异性和对非哺乳动物的限制推断它们可能作为抗微生物药物的高度特异性靶标而具有最小的脱靶效应.
