, ▁is ▁fund ament ally ▁a ▁rib oz yme , ▁composed ▁of ▁R NA ▁t ert i ary ▁struct ural ▁mot ifs ▁that ▁are ▁often ▁coordin ated ▁to ▁metal ▁ ions ▁such ▁as ▁M g 2 + ▁as ▁c of act ors . ▁In ▁a ▁model ▁system , ▁there ▁is ▁no ▁requirement ▁for ▁div al ent ▁c ations ▁in ▁a ▁five - n uc le ot ide ▁R NA ▁catal yz ing ▁trans - phen yl al an ation ▁of ▁a ▁four - n uc le ot ide ▁substr ate ▁with ▁ 3 ▁base ▁pairs ▁complement ary ▁with ▁the ▁catal yst , ▁where ▁the ▁catal yst / substr ate ▁were ▁de vised ▁by ▁trunc ation ▁of ▁the ▁C 3 ▁rib oz yme . ▁ ▁The ▁best - stud ied ▁rib oz ym es ▁are ▁probably ▁those ▁that ▁cut ▁themselves ▁or ▁other ▁R N As , ▁as ▁in ▁the ▁original ▁discovery ▁by ▁C ech ▁and ▁Alt man . ▁However , ▁rib oz ym es ▁can ▁be ▁designed ▁to ▁catal y ze ▁a ▁range ▁of ▁re actions ▁( see ▁below ), ▁many ▁of ▁which ▁may ▁occur ▁in ▁life ▁but ▁have ▁not ▁been ▁discovered ▁in ▁cells . ▁ ▁R NA ▁may ▁catal y ze ▁fol ding ▁of ▁the ▁ ▁path ological ▁protein ▁con formation ▁of ▁a ▁pr ion ▁in ▁a ▁manner ▁similar ▁to ▁that ▁of ▁a ▁ch aper on in . ▁ ▁Rib oz ym es ▁and ▁the ▁origin ▁of ▁life ▁ ▁R NA ▁can ▁also ▁act ▁as ▁a ▁her edit ary ▁mole c ule ,