▁human ▁body ▁over ▁time ▁due ▁to ▁its ▁frequent ▁usage ▁in ▁indust ries ▁and ▁presence ▁in ▁our ▁environment . ▁In hal ation ▁of ▁lead ▁can ▁have ▁effects ▁that ▁can ▁be ▁range ▁from ▁subt le ▁sympt oms ▁to ▁serious ▁ill ness es . ▁It ▁is ▁possible ▁that ▁presence ▁of ▁lead ▁in ▁our ▁bi ological ▁systems ▁can ▁indu ce ▁catal ysis ▁by ▁lead ▁ ions . ▁Since ▁lead zym e ▁is ▁a ▁relatively ▁simple ▁mot if ▁i . e ., ▁it ▁has ▁a ▁simple ▁fol d , ▁it ▁appears ▁that ▁there ▁are ▁many ▁sequences ▁in ▁the ▁genom es ▁of ▁many ▁natural ▁systems ▁which ▁can ▁potentially ▁fol d ▁into ▁a ▁lead zym e ▁structure . ▁A ▁simple ▁search ▁for ▁this ▁R NA ▁mot if ▁in ▁the ▁genom es ▁of ▁humans , ▁D ros oph ila ▁mel an og aster , ▁Ca en or hab d itis ▁eleg ans ▁and ▁Arab id opsis ▁th al iana ▁revealed ▁that ▁on ▁average ▁this ▁mot if ▁is ▁present ▁with ▁the ▁frequency ▁of ▁ 2 - 9 ▁mot ifs ▁for ▁ 1 ▁M bp ▁of ▁DNA ▁sequence . ▁They ▁also ▁showed ▁that ▁lead zym e ▁mot if ▁is ▁very ▁common ▁in ▁the ▁m R NA ▁sequences ▁of ▁these ▁organ isms ▁as ▁well . ▁Thus , ▁these ▁sequences ▁could ▁potentially ▁self - cle ave ▁in ▁the ▁presence ▁of ▁lead ▁ ions . ▁The ▁target ing ▁of ▁these ▁R NA ▁mot ifs ▁by ▁lead ▁in ▁m R N As ▁and ▁other ▁R N As ▁may ▁explain ▁lead - medi ated ▁to x icity ▁resulting