International Journal of Astrobiology

Table of Contents - 2009 - Volume 8, Issue 02  

Research Article

Heat-initiated prebiotic formation of peptides from glycine/aspartic acid and glycine/valine in aqueous environment and clay suspension

Chandra Kala Panta1 c1, Hem Lataa1, Hari Datt Pathaka1 and Mohan Singh Mehataa2 c2

a1 Department of Chemistry, DSB Campus, Kumaun University, Nainital 263 002, Uttarakhand, India

a2 Photophysics Laboratory, Department of Physics, Kumaun University, Nainital, India; present address RIES, Hokkaido University, Sapporo 001-0020, Japan

Abstract

The effect of heat on the reaction system of glycine/aspartic acid and glycine/valine in the aqueous environment as well as in montmorillonite clay suspension with or without divalent cations (Ca2+, Mg2+ and Ni2+) has been investigated at 85°C±5°C for varying periods under prebiotic drying and wetting conditions. The resulting products were analysed and characterized by chromatographic and spectroscopic methods. Peptide formation appears to depend on the duration of heat effect, nature of reactant amino acids and, to some extent, on montmorillonite clay incorporated with divalent cations. In the glycine/aspartic acid system, oligomerization of glycine was limited up to trimer level (Gly)3 along with the formation of glycyl-aspartic acid, while linear and cyclic peptides of aspartic acid were not formed, whereas the glycine/valine system preferentially elongated homo-oligopeptide of glycine up to pentamer level (Gly)5 along with formation of hetero-peptides (Gly-Val and Val-Gly). These studies are relevant in the context of the prebiotic origin of proteins and the role of clay and metal ions in condensation and oligomerization of amino acids. The length of the bio-oligomer chain depends upon the reaction conditions. However, condensation into even a small length seems significant, as the same process would have taken millions of years in the primitive era of the Earth, leading to the first proteins.

(Received February 01 2009)

(Accepted May 27 2009)

(Online publication July 14 2009)

Key Words:

Correspondence:

c1 email: ckp_ku@yahoo.co.in

c2 email: msmehata@yahoo.com