Title
Effect of Stearylguanidinium-Modified POPC Vesicles on the Melting Behavior of tRNA Molecules
Author
Keishi Suga, Nozomi Watanabe, and Hiroshi Umakoshi
Year
2016
Journal
The Journal of Physical Chemistry B
Abstract
Lipid membranes interact with biomolecules via non-covalent bonding interactions, wherein the physicochemical membrane properties are key factors in the recognition and rearrangement of biomolecule conformation. In this study, vesicles were prepared using 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and stearylguanidinium (SG) to improve the affinity between the membrane and transfer RNA (tRNA). Membrane fluidity decreased and dehydration of the membrane surface increased with increasing SG levels, suggesting that SG molecules could make the membrane rigid and induce a liquid-ordered (lo)-like phase. The binding constant (Ka) between nucleotide and lipid was evaluated by turbidity analysis; the Ka value for POPC/SG = (86/14) was 2.9 × 10^4 M-1, but was slightly decreased by vesicles in the lo-like phase. CD spectra of tRNA by the presence of POPC/SG vesicles showed C-G selective base cleavage in tRNA during heat denaturation. POPC/SG = (61/39) and POPC/SG = (40/60) effectively led to C-G base pair cleavage at the melting temperature of tRNA.
Instrument
J-820
Keywords
Circular dichroism, DNA structure, Vesicle interactions, Biochemistry