Essential structures of a self-aminoacylating RNA.
Comparison of six independent self-aminoacylating RNAs derived from selection-amplification, as well as deletion, addition, substitution, fragmentation of one particular RNA, are used to analyze the requirements for the RNA-catalyzed aminoacylation. All elements required for catalysis by one RNA family: sequence at the 3' acceptor end, calcium and magnesium sites, as well as the Phe-AMP substrate site and the essential 5' triphosphate terminus, are closely grouped near a bihelix junction in the parental molecule. All elements of the active center for aminoacyl transfer can therefore be captured by a peripherally-deleted helix junction RNA, defining a much smaller 43 nucleotide ribozyme, of which only 17 nucleotides were initially randomized. It appears that a complex RNA active center can be assembled by specifying unexpectedly few nucleotides, perhaps with a critical contribution from an essential calcium ion.
Illangasekare
M
M
Department of MCD Biology, University of Colorado, Boulder 80309-0347, USA.
Kovalchuke
O
O
Yarus
M
M
D000215:Acylation; D000249:Adenosine Monophosphate / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010649:Phenylalanine / Q000378:metabolism; D012313:RNA / Q000737:chemistry* / Q000378:metabolism*; D016337:RNA, Catalytic / Q000737:chemistry / Q000378:metabolism; D017384:Sequence Deletion
D008670:Metals; D016337:RNA, Catalytic; D000249:Adenosine Monophosphate; D010649:Phenylalanine; D012313:RNA