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Stereoselective arginine binding is a phylogenetically conserved property of group I self‐splicing RNAs.
Author(s) -
Hicke B.J.,
Christian E.L.,
Yarus M.
Publication year - 1989
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1989.tb08562.x
Subject(s) - biology , genetics , rna splicing , arginine , group (periodic table) , property (philosophy) , alternative splicing , conserved sequence , computational biology , rna , evolutionary biology , base sequence , gene , exon , amino acid , philosophy , chemistry , organic chemistry , epistemology
We have examined the reaction of GTP with RNA polymerase transcripts containing the self‐splicing RNA precursors from the Neurospora crassa Cob1 intron, and from introns in the sunY, nrdB and td genes of bacteriophage T4. In each case, we find a low Km for GTP (between 0.8 and 11 microM), accompanied by competitive inhibition of the GTP reaction by L‐arginine, as was found for the previously examined Tetrahymena nuclear pre‐rRNA intron. Trials with the 20 standard amino acids show that inhibition in all cases is specific to the arginine side‐chain. L‐arginine binds with similar affinity to all introns studied, the Ki's ranging from 4.3 to 21 mM. Strikingly, the relative binding preference of the RNAs for L‐ versus D‐arginine is highly conserved: the ratio of L‐arg Ki/D‐arg Ki, the stereoselectivity, is always close to 2. Because of the conservation of GTP and arginine binding constants and particularly because of the conserved stereoselectivity, we conclude that the evolution of an effective group I RNA transesterification catalyst necessarily produces a specific and stereoselective RNA binding site for a single amino acid. This suggests that selection for an ancient group I RNA could have fortuitously initiated the specific association of RNA sequences with amino acids, a first step toward the genetic code.