[50] Ribosomal peptidyltransferase: The fragment reaction
1971; Academic Press; Linguagem: Inglês
10.1016/s0076-6879(71)20052-5
ISSN1557-7988
Autores Tópico(s)Peptidase Inhibition and Analysis
ResumoPeptide bond formation in protein biosynthesis takes place by transfer of the growing peptidyl group from the CCA terminus of one molecule of tRNA to an aminoacyl group attached to the CCA terminus of a second molecule of tRNA. This chapter describes a method for assay of the fragment reaction using CACCA-(AcLeu) or UACCA-(AcLeu) and puromycin as substrates; and a method for preparing the Ac[3H]Leu-oligonucleotides. The chapter recommends the Ac[3H]Leu derivatives of CACCA and UACCA as peptidyl donor substrates, because: (a) they have good activity in the fragment reaction; (b) they are suitable for binding studies; (c) they are obtained in good yield; and (d) radioactive leucine is available at high specific activity. Peptidyltransferase is integrated into the structure of the larger ribosomal subunit in all species that have so far been examined, for example, E.coli, B.subtilis, Anacystis montana, yeast, protozoa, rat liver, and human tonsils. The ribosomal peptidyltransferases in these various species are similar to one another in many respects, but a difference between the fine structures at the catalytic centers of 70 S and 80 S ribosomes is indicated by differences in sensitivity to antibiotics.
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