Ribozyme-catalyzed aminoacylation from CoA thioesters.
Coenzyme A (CoA) thioesters play essential roles in modern metabolism. To demonstrate plausible biochemical functions of thioesters in the RNA world, we have isolated a new class of ribozymes (ACT) that catalyze self-aminoacylation from a number of CoA thioesters with catalytic efficiencies ranging from 7000 to 24 000 M(-1) x min(-1). Active thioester substrates are required to contain both a free alpha-amino group in the acyl moiety and a CoA as the thiol component. We hypothesize ribozyme-based aminoacylation systems using aminoacyl thioesters of CoA as the ancestors of modern aminoacyl tRNA synthetases. On the basis of our previous results [Huang et al. (2000) Biochemistry 39, 15548-15555; Coleman and Huang (2002) Chem. Biol. 9, 1227-1236], an extensive RNA-catalyzed "metabolic pathway" involving CoA and its thioesters is proposed. Complex contemporary metabolic systems could have evolved from the proposed ribozyme pathways.
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Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406-5043, USA.
Huang
Faqing
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D020413:3' Untranslated Regions / Q000378:metabolism; D020121:5' Untranslated Regions / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D001710:Biotin / Q000378:metabolism; D002384:Catalysis; D004952:Esters; D015723:Gene Library; D007700:Kinetics; D008969:Molecular Sequence Data; D012313:RNA / Q000378:metabolism; D016337:RNA, Catalytic / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*; D046249:Transfer RNA Aminoacylation
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D000214:Acyl Coenzyme A; D004952:Esters; C034477:RNA primers; D016337:RNA, Catalytic; D013438:Sulfhydryl Compounds; D012313:RNA; D001710:Biotin; D012194:RNA-Directed DNA Polymerase