Title
Synthesis, characterization, crystal structure of RNA targeted L- and D-phenylalanine-(1, 10-phen)-copper(II) conjugate complexes; Comparative in vitro RNA binding profile of enantiomers and their biological evaluation by morphological studies and antibacterial activity
Author
Surbhi Sharma, Loïc Toupet, Musheer Ahmad, Farukh Arjmand
Year
2016
Journal
RSC Advances
Abstract
New ternary chiral Cu(II) complexes 1a and b derived from L- and D-phenylalanine and 1, 10-phenanthroline were synthesized and characterized thoroughly by single crystal X−ray diffraction and other spectroscopic techniques viz., UV−vis, IR, EPR, ESI−MS and elemental analysis. Complexes crystallized in the monoclinic P21 space group possessing the lattice parameters as, a = 5.74690(10) Å, b = 20.6365(2) Å, c = 9.28010(10) Å, α = γ = 90°, β = 98.2040(10) in complex 1a and a = 5.728(5) Å, b = 20.587(5) Å, c = 9.252(5)Å, α = γ = 90°, β = 98.308(5) in complex 1b per unit cell, respectively. Comparative in vitro RNA binding studies of L– and D–enantiomeric complexes, 1a and b were carried out by a variety of optical spectroscopies viz., UV−vis, fluorescence, circular dichroism and since copper being a redox metal ion, cyclic voltammetry was employed to evaluate the enantioselective RNA binding. The results demonstrated that L–enantiomer of Cu(II) complex, 1a binds more avidly to t–RNA motif in comparison to D–enantiomer thereby underlining the differential disposition of enantiomers and site preference of RNA for L-enantiomer than D- analog. Further, comparative Kb, K and Ksv values of L– and D–complexes demonstrated significant increase in case of L–enantiomer of copper complex, 1a in comparison to its D–enantiomeric form, 1b. SEM analysis divulged surface morphological alteration of complexes 1a and b, evidenced by the formation of hollow tubes and concrete like structure with RNA condensate which was less pronounced in SEM micrographs of complex 1b condensate. Antimicrobial activity of complexes 1a and b carried by agar well diffusion method demonstrated significant antibacterial activity.
Instrument
J-815
Keywords
Circular dichroism, DNA structure, Biochemistry