Discrimination against misacylated tRNA by chloroplast elongation factor Tu

Open Access
Publisher Website
Google Scholar
Abstract
Chloroplast elongation factor Tu was purified from Pisum sativum and the binding properties of glutamylated chloroplast tRNAs were studied by gel‐permeation chromatography. Whereas chloroplast Glu‐tRNAGlu is efficiently bound by this factor, the misacylated Glu‐tRNAGin does not interact with chloroplast elongation factor Tu · GTP and is thus efficiently excluded from protein synthesis. Comparison with the behaviour of Escherichia coli elongation factor Tu · GTP shows that this factor, which is not confronted with the in vivo misacylation phenomenon of organelles, binds both Glu‐tRNAGlu and Glu‐tRNAGln from chloroplasts with approximately equal efficiency.