NDLI: Affinity of Smectite and Divalent Metal Ions (Mg$^{2+}$, Ca$^{2+}$, Cu$^{2+}$) with L-leucine: An Experimental and Theoretical Approach Relevant to Astrobiology

Content Provider	Springer Nature Link
Author	Pandey, Pramod Pant, Chandra Kala Gururani, Kavita Arora, Priyanka Pandey, Neetu Bhatt, Preeti Sharma, Yogesh Negi, Jagmohan Singh Mehata, Mohan Singh
Copyright Year	2015
Abstract	Earth is the only known planet bestowed with life. Several attempts have been made to explore the pathways of the origin of life on planet Earth. The search for the chemistry which gave rise to life has given answers related to the formation of biomonomers, and their adsorption on solid surfaces has gained much attention for the catalysis and stabilization processes related to the abiotic chemical evolution of the complex molecules of life. In this communication, surface interactions of L-leucine (Leu) on smectite (SMT) group of clay (viz. bentonite and montmorillonite) and their divalent metal ion (Mg$^{2+}$, Ca$^{2+}$ and Cu$^{2+}$) incorporated on SMT has been studied to find the optimal conditions of time, pH, and concentration at ambient temperature (298 K). The progress of adsorption was followed spectrophotometrically and further characterized by FTIR, SEM/EDS and XRD. Leu, a neutral/non polar amino acid, was found to have more affinity in its zwitterionic form towards Cu$^{2+}$- exchanged SMT and minimal affinity for Mg$^{2+}$- exchanged SMT. The vibrational frequency shifts of —NH$_{3}$ $^{+}$ and —COO$^{−}$ favor Van der Waal’s forces during the course of surface interaction. Quantum calculations using density functional theory (DFT) have been applied to investigate the absolute value of metal ion affinities of Leu (Leu—M$^{2+}$ complex, M = Mg$^{2+}$, Ca$^{2+}$, Cu$^{2+}$) with the help of their physico-chemical parameters. The hydration effect on the relative stability and geometry of the individual species of Leu—M$^{2+}$ × (H$_{2}$O)$_{n}$, (n =2 and 4) has also been evaluated within the supermolecule approach. Evidence gathered from investigations of surface interactions, divalent metal ions affinities and hydration effects with biomolecules may be important for better understanding of chemical evolution, the stabilization of biomolecules on solid surfaces and biomolecular-metal interactions. These results may have implications for understanding the origin of life and the preservation of biomarkers.
Starting Page	411
Ending Page	426
Page Count	16
File Format	PDF
ISSN	01696149
Journal	Origins of Life and Evolution of Biospheres
Volume Number	45
Issue Number	4
e-ISSN	15730875
Language	English
Publisher	Springer Netherlands
Publisher Date	2015-05-08
Publisher Place	Dordrecht
Access Restriction	Subscribed
Subject Keyword	Amino acids Smectite Metal ions Surface interaction DFT Origin of life Life Sciences Astrophysics and Astroparticles Earth Sciences Astronomy, Observations and Techniques Biochemistry
Content Type	Text
Resource Type	Article
Subject	Medicine Ecology, Evolution, Behavior and Systematics Space and Planetary Science

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