Binding of Aminoacyl tRNA to the A Site

Binding of Aminoacyl tRNA to the A Site

Binding of Aminoacyl tRNA to the A Site - In prokaryotes EF-Tu and EF-Ts are required for binding the aminoacyl tRNA (aa.tRNA) to the ribosome. EF-Tu forms a ternary complex with aa.tRNA and GTP. The formation of the complex is catalysed by EF- Ts

aa - tRNA + EF- Tu + GTP----------->(aa - tRNA.EF - Tu.GTP)
	Ternary complex

Transfer of the aa - tRNA from the ternary complex to the A site of the ribosome now takes place.

(aa -tRNA.EF-Tu.GTP) +

Ribosome ---->

(aa -tRNA.RIbosome)+

(EF -Tu.GDP)+

Recycling of GDP now takes place from the (EF-Tu.GDP) complex .

(EF -Tu.GDP)+

GTP

(EF -Tu.GDP)+

GDP

(EF -Tu.GDP) now reacts with another aa-tRNA. The net result is that aminoacyl t RNA enters the A site.

In eukaryotes, despite the fact that binary and ternary complexes have not been isolated from tissues, the following scheme may be operating.

(i) EF-1 + GTP ----> (EF-1.GTP) (binary complex)
(ii) (EF-1.GTP) + (aa-tRNA)----> (aa-tRNA.EF-1.GTP)
			(Ternary complex)
(iii) (aa-tRNA.EF-1.GTP) +	Ribosomes---->	(aa-tRNA Ribosomes + )	(EF-1.GTP) +	Pi
			Factors
(EF-1.GTP) +	GTP +	GTP	------------------>	(EF-1.GTP) + GDP

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Protein Synthesis Part 1 Release of Deacylated tRNA Hydrolysis of GTP Locking and Unlocking Ribosome Model inchworn Theory Conformational Changes Recognition of the Termination Signal Release of the Polypeptide Chain Prokaryote and Eukaryote Release Factors Processing Polypeptide Chain Rate of Protein Synthesis Signal Hypothesis Prokaryote and Eukaryote Protein Synthesis Teminism

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