Emanuel Goldman, New Jersey Medical School, Newark, New Jersey, USA
Published online: September 2008
DOI: 10.1002/9780470015902.a0000878.pub2
Transfer ribonucleic acid (tRNA) is the class of molecules that decode the genetic code and link the coded information to their attached amino acids. These become constituents of the protein specified by the gene.
Keywords: protein synthesis; genetic code; ribosomes; aminoacylation
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Figure 1.
tRNA determines which amino acid goes into protein. Depicted are two ribosomes at Cys codons (UGU, UGC) on an mRNA; Cys‐tRNACys normally decodes these codons, inserting cysteine in protein, but after treatment with Raney nickel, Cys‐tRNACys is converted to Ala‐tRNACys, which now inserts alanine in protein at positions normally occupied by cysteine. |
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Figure 2.
(a) Cloverleaf diagram is the two‐dimensional folding pattern of the transfer RNA (tRNA) molecule. Nucleotide bases found almost universally in the same position in all tRNA sequences are indicated. The ladder‐like stems are made up of complementary bases in different parts of the polynucleotide chain that pair up and form hydrogen bonds, causing the chain to fold back on itself. The number of nucleotides in the various stems and loops is generally constant except for two parts of the D loop designated α and β (which consist of 1–3 three nucleotides in different tRNAs) and the variable loop (which usually has four or five nucleotides but may have as many as 21). Abbreviations: A, adenosine; G, guanosine; C, cytidine; U, uridine; R, adenosine or guanosine; Y, cytidine or uridine; T, ribothymidine; and y, pseudouridine. (b) Folding pattern of the polynucleotide chain in yeast phenylalanine tRNA is diagrammed. The sugar‐phosphate backbone of the molecule is represented as a coiled tube, with the cross rungs standing for the nucleotide base pairs in the stem regions. The short rungs indicate bases that are not involved in base–base hydrogen bonding. The colours refer to the cloverleaf diagram in part (a). Reproduced from Rich A and Kim SH (1978) The three‐dimensional structure of transfer RNA. Scientific American238: 52–62. |
Further Reading
Agris PF, Vendeix FA and Graham WD (2007) tRNA's wobble decoding of the genome: 40 years of modification. Journal of Molecular Biology 366: 1–13.
Bjork GR (1995) Genetic dissection of synthesis and function of modified nucleosides in bacterial transfer RNA. Progress in Nucleic Acid Research and Molecular Biology 50: 263–338.
Eggertsson G and Söll D (1988) Transfer ribonucleic acid‐mediated suppression of termination codons in E. coli. Microbiological Reviews 52: 354–374.
Giegé R, Sissler M and Florentz C (1998) Universal rules and idiosyncratic features in tRNA identity. Nucleic Acids Research 26: 5017–5035.
Goldman E and Jakubowski H (1990) Uncharged tRNA, protein synthesis, and the bacterial stringent response. Molecular Microbiology 4: 2035–2040.
Journal of Biosciences (2006) History of tRNA Research. Journal of Biosciences 31: 437–496. http://www.ias.ac.in/jbiosci/oct2006/contents.htm.
Parker J (1989) Errors and alternatives in reading the universal genetic code. Microbiological Reviews 53: 273–298.
RajBhandary UL (1994) Initiator transfer RNAs. Journal of Bacteriology 176: 547–552.
Rich A and RajBhandary UL (1976) Transfer RNA: molecular structure, sequence and properties. Annual Review of Biochemistry 45: 805–860.
Schimmel PR, Söll D and Abelson JN (eds) (1979) Transfer RNA: Structure, Properties and Recognition. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press.
Söll D, Abelson JN and Schimmel PR (eds) (1980) Transfer RNA: Biological Aspects. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press.
Söll D and RajBhandary UL (eds) (1995) tRNA. Washington, DC: American Society for Microbiology.
Wilson DN and Nierhaus KH (2006) The E‐site story: the importance of maintaining two tRNAs on the ribosome during protein synthesis. Cellular and Molecular Life Sciences 63: 2725–2737.
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