Transfer RNA (tRNA): Difference between revisions

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Frédéric Dardel, Wayne Decatur, Michal Harel, Alexander Berchansky, Ann Taylor, Joel L. Sussman, Karsten Theis

Revision as of 16:50, 1 November 2018 view source Karsten Theis (talk \| contribs) Macro 4,174 edits No edit summary ← Older edit		Revision as of 00:32, 5 November 2018 view source Karsten Theis (talk \| contribs) Macro 4,174 edits No edit summary Newer edit →
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	'''Interaction with ribosomes and mRNA.''' Ribosomes have multiple binding sites for tRNA. During protein synthesis, the partially synthesized protein is always covalently attached to a tRNA bound to the ribosome. When a new tRNA charged with a single amino acid binds to the ribosome, the partially synthesized (nascent) protein is transferred onto the new amino acid (the ester bond between nascent protein and tRNA is broken and a new peptide bond between nascent protein and the new amino acid is formed), elongating the nascent protein by one amino acid. This chemistry happens at the 3’-OH of the acceptor stem of tRNA. The other end of tRNA has a role in selecting the correct tRNA (charged with the correct amino acid) through interactions between the anticodon loop at the other end of tRNA with codons on the messenger RNA bound to the ribosome and presented to the tRNA.		'''Interaction with ribosomes and mRNA.''' <scene name='43/433638/Ribosome/2'>Ribosomes</scene> have multiple binding sites for tRNA. During protein synthesis, the partially synthesized protein is always covalently attached to a tRNA bound to the ribosome. When a new tRNA charged with a single amino acid binds to the ribosome, the partially synthesized (nascent) protein is transferred onto the new amino acid (the ester bond between nascent protein and tRNA is broken and a new peptide bond between nascent protein and the new amino acid is formed), elongating the nascent protein by one amino acid. This chemistry happens at the 3’-OH of the acceptor stem of tRNA. The other end of tRNA has a role in selecting the correct tRNA (charged with the correct amino acid) through interactions between the anticodon loop at the other end of tRNA with codons on the messenger RNA bound to the ribosome and presented to the tRNA.

	There are special mechanisms to get protein synthesis started (initiation), and to end it (termination). Initiator tRNA is a Met-tRNA which recognizes the methionine codon which is the initial codon in protein synthesis. Initiator-tRNA differs from the protein elongation Met-tRNA by forming a complex with IF-2 and GTP, by bonding to the ribosomal P-site and exclusion from bonding to the ribosomal A-site[1].		There are special mechanisms to get protein synthesis started (initiation), and to end it (termination). Initiator tRNA is a Met-tRNA which recognizes the methionine codon which is the initial codon in protein synthesis. Initiator-tRNA differs from the protein elongation Met-tRNA by forming a complex with IF-2 and GTP, by bonding to the ribosomal P-site and exclusion from bonding to the ribosomal A-site[1].