Aminoacyl derivatives of nucleosides, nucleotides, and polynucleotides. XVII. L-Phenylalanine esters of open-chain analog of adenosine as substrates for ribosomal peptidyl transferase

Abstract

The chemical synthesis of the open-chain analogs of 2'-and 3 '-0-(L-phenylalanyl) and 2',3'-bis-O-(~-phenylalanyl)adenosine (compounds Ih-j) is described. Compounds Ih and Ij were active in the release of N-Ac-Phe-tRNA catalyzed by ribosomes: at 0.1 mM, compound Ih released 8 and Ij, 12

Aminoacyl derivatives of nucleosides, nucleotides, and polynucleotides. XIX. Nonisomerizable 2'- and 3'-O-aminoacyldinucleoside phosphates. Chemical synthesis and acceptor activity in the ribosomal peptidyltransferase reaction

“…The results presented here are fully consistent with the report of Hussain and Ofengand (1973) who showed that the 2 '-phenylalanyl ester of the "open-chain" analog of adeno-sine8 was inactive in the peptidyltransferase reaction, whereas a mixture of the 2' and 3' isomers prepared by chemical synthesis was active. We recently reported that the open-chain analog of 3'-A-Phe is moderately active and that its 2' isomer is inactive (Chládek et al, 1973). Both isomers were prepared by chemical synthesis.9 Therefore, we can conclude that the Ac-[3H]Phe residue released during the peptidyltransferase reaction from the donor molecule was determined, as described in Figures 2 and 4.…”

“…Assay of Peptidv¡transferase Actiaty. Peptidyltransferase activity was measured essentially as described earlier (Chládek et al, 1973). Each reaction mixture of 0.1 ml contained: 0.05 m Tris-HCl (pH 7.4), 0.10 m NH.Cl, 0.01 m MgCl,, 3.7 A,60 units of NH4Cl-washed ribosomes, 10 /¿g of poly(U), and 0.12 A;C>0 unit of 7V-acetyl-[3H]phenylaIanyI-tRNA (2000 cpm).…”

“…On the basis of the structure and activity of the antibiotic puromycin, which can be considered a simple 3 '-O-aminoacyl-tRNA analog, and the inactivity of its 2' analog in the inhibition of polypeptide synthesis (Nathans and Neidle, 1963), it has been assumed that 3'-O-aminoacyl-tRNA is an active species in protein biosynthesis. Moreover, we have recently observed (Chládek et al, 1973) that the 3'-phenylalanyl ester of "opent From the Michigan Cancer Foundation, Detroit, Michigan 48201.…”

“…We have recently shown(Ringer and Chládek, 1974a), using the same models described in this communica-7 Interestingly,Hecht et al (1973) observed that when the terminal adenosine unit of the 3' end of tRNA was replaced with either 2'-0methyladenosine or 3 '-O-methyladenosinc there was no charging by aminoacylsynthctase.s This compound was prepared from tRNA, which was oxidized by periodate, reduced by borohydridc, charged enzymatically (presumably at the 2' position), and then digested by pancreatic RNasc. 9 In the case of the open-chain analog, however, there is a substantial decrease in acceptor activity compared to A-Phe that is attributed to the absence of the relatively rigid ribofuranosc ring(Chládek et al, 1973).2730 biochemistry, vol.13, no. 13, 1974…”

Terminal oxidation-reduction of N-acetyl-phenylaianyl-tRNA blocks initiation complex formation with Escherichia coli 30S ribosomal subunits

“…reactions of protein synthesis are not known with certainty, although there is some indication that EFTu-dependent binding to the ribosomal A site may either be 2'-specific or non-stereoselective (11,12). The stereospecificity of peptidyl transferase at the P site is likewise not known, although it has been shown by the use of different model substrates that the A site is 3'-specific (2,(13)(14)(15). Our data would indicate that initiation factor recognition may also be specific for the 3'-ester of AA-tRNA, although we cannot at this time rule out the possibility that the lack of activity is caused by structural alterations correlated with the opening of the ribose ring.…”