The evolution of Class II Aminoacyl-tRNA synthetases and the first code

Temple F Smith; Hyman Hartman

doi:10.1016/j.febslet.2015.10.006

The evolution of Class II Aminoacyl-tRNA synthetases and the first code

FEBS Lett. 2015 Nov 30;589(23):3499-507. doi: 10.1016/j.febslet.2015.10.006. Epub 2015 Oct 20.

Authors

Temple F Smith¹, Hyman Hartman²

Affiliations

¹ BioMedical Engineering, Boston University, Boston, MA 02215, USA. Electronic address: templesmith1@comcast.net.
² Earth, Atmosphere, and Planetary Science Department, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Electronic address: hhartman@mit.edu.

PMID: 26472323
DOI: 10.1016/j.febslet.2015.10.006

Abstract

Class II Aminoacyl-tRNA synthetases are a set of very ancient multi domain proteins. The evolution of the catalytic domain of Class II synthetases can be reconstructed from three peptidyl-hairpins. Further evolution from this primordial catalytic core leads to a split of the Class II synthetases into two divisions potentially associated with the operational code. The earliest form of this code likely coded predominantly Glycine (Gly), Proline (Pro), Alanine (Ala) and "Lysine"/Aspartic acid (Lys/Asp). There is a paradox in these synthetases beginning with a hairpin structure before the Genetic Code existed. A resolution is found in the suggestion that the primordial Aminoacyl synthetases formed in a transition from a Thioester world to a Phosphate ester world.

Keywords: Aminoacyl-tRNA-synthetase; Evolution; Operational-code; Thioester.

MeSH terms

Amino Acyl-tRNA Synthetases / chemistry
Amino Acyl-tRNA Synthetases / metabolism*
Catalytic Domain
Evolution, Molecular*
Models, Molecular

Substances

Amino Acyl-tRNA Synthetases