It has been hypothesized that the ribosome gains additional fidelity during protein translation by probing structural differences in tRNA species. We measure the translocation kinetics of different tRNA species through ∼3 nm diameter synthetic nanopores. Each tRNA species varies in the time scale with which it is deformed from equilibrium, as in the translocation step of protein translation. Us...

1. A procedure for measuring rates of aminoacyl-tRNA synthesis in vitro and in intact leaves is presented. 2. Leaf discs showed rates close to those of intact leaves. 3. Cell-free preparations showed similar rates when assayed by pyrophosphate exchange, but actual aminoacyl-tRNA formation rates appeared to be much lower. Evidence is presented that dilution of supplied labelled amino acids was a...

The role of platelets in hemostasis and thrombosis is clearly established; however, the mechanisms by which platelets mediate inflammatory and immune pathways are less well understood. Platelets interact and modulate the function of blood and vascular cells by releasing bioactive molecules. Although the platelet is anucleate, it contains transcripts that may mirror disease. Platelet mRNA is onl...

The role of platelets in hemostasis and thrombosis is clearly established; however, the mechanisms by which platelets mediate inflammatory and immune pathways are less well understood. Platelets interact and modulate the function of blood and vascular cells by releasing bioactive molecules. Although the platelet is anucleate, it contains transcripts that may mirror disease. Platelet mRNA is onl...

The complete resolution of the initiation and transfer factors of wheat embryo supernatant is described. Two factors function in chain initiation, as ascertained by (a) their requirement for the formation of a ribosome-messenger RNA complex whose capacity for ammo acid incorporation is insensitive to aurintricarboxylic acid; and (b) their participation in the tobacco mosaic virus RNA-dependent ...

The mechanism by which an aminoacyl ribonucleic acid synthetase recognizes its transfer ribonucleic acid substrate constitutes one of the central problems in biochemical genetics. Obviously this problem cannot be solved without a thorough understanding of the structure of both enzyme and substrate. Although work on the structure of tRNAr has yielded signal results during the last few years (l-3...

Translocation of the tRNA-mRNA complex is a fundamental step in the elongation cycle of protein synthesis. Our studies show that the ribosome can translocate a P-site-bound tRNA(Met) with a break in the phosphodiester backbone between positions 56 and 57 in the TPsiC-loop. We have used this fragmented P-site-bound tRNA(Met) to identify two 2'-hydroxyl groups at positions 71 and 76 in the 3'-acc...

It is now established that the biological function of transfer RNA (sRNA) is to accept amino acid at a terminus of the chain, resulting in the formation of aminoacylsRNA,1-3 and to transfer the amino acid from that aminoacyl-sRNA into a polypeptide chain by interacting with messenger RNA on the surface of polyribosomes.4, I A number of indirect observations6-9 suggest that the sites for these r...

RNase T2 enzymes are produced by a wide range of organisms and have been implicated to function in diverse cellular processes, including stress-induced anticodon loop cleavage of mature tRNAs to generate tRNA halves. Here we describe a family of eight RNase T2 genes (RNT2A-RNT2H) in the ciliate Tetrahymena thermophila. We constructed strains lacking individual or combinations of these RNT2 gene...

The basic steps of protein synthesis are carried out by the ribosome, a very large and complex ribonucleoprotein particle. In keeping with its proposed emergence from an RNA world, all three of its core mechanisms-aminoacyl-tRNA selection, catalysis of peptide bond formation and coupled translocation of mRNA and tRNA-are embodied in the properties of ribosomal RNA, while its proteins play a sup...