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Title: Experimental and theoretical investigations of infrared multiple photon dissociation spectra of arginine complexes with Zn 2+ and Cd 2+
Arginine (Arg) complexes with Zn 2+ and Cd 2+ were examined by infrared multiple photon dissociation (IRMPD) action spectroscopy using light from a free electron laser. Electrospray ionization generated complexes of deprotonated Arg with Zn 2+ , [Zn(Arg–H)] + , and Arg with CdCl + , CdCl + (Arg). Possible low-energy conformers of these species were found using quantum chemical calculations, and their calculated IR spectra were compared to experimentally measured IRMPD spectra. Calculations were performed at the B3LYP/6-311+G(d,p) level for Zn 2+ complexes and B3LYP/def2-TZVP with an SDD effective core potential on cadmium for CdCl + complexes. [Zn(Arg–H)] + was found to adopt a charge-solvated, tridentate [N,CO − ,N ω ′] structure where Zn 2+ binds to the backbone amine, carbonyl oxygen, and side-chain terminal guanidine nitrogen (N ω ′). The CdCl + (Arg) species was suggested to be a mixture of a dominant (∼85%) charge-solvated, tridentate [N,CO,N ω ′] structure where the CdCl + binds to the backbone amine, carbonyl, and side-chain imine (N ω ′) and a minor (∼15%) bidentate [N,CO − ](N ω ′H 2 + ) zwitterionic structure where the metal center binds to the backbone amine and carbonyl oxygen with intramolecular proton migration from the hydroxyl to the N ω ′ guanidine nitrogen (as designated in parenthesis).  more » « less
Award ID(s):
1664618
NSF-PAR ID:
10093403
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Physical Chemistry Chemical Physics
Volume:
20
Issue:
31
ISSN:
1463-9076
Page Range / eLocation ID:
20712 to 20725
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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