Abstract
An infrared free electron laser (IR-FEL) can decompose aggregated proteins by excitation of vibrational bands. In this study, we prepared hybrid materials of protein (human serum albumin; HSA) including several new Schiff base Zn(II) complexes incorporating amino acid (alanine and valine) or dipeptide (gly-gly) derivative moieties, which were synthesized and characterized with UV-vis, circular dichroism (CD), and IR spectra. Density functional theory (DFT) and time dependent DFT (TD-DFT) calculations were also performed to investigate vibrational modes of the Zn(II) complexes. An IR-FEL was used to irradiate HSA as well as hybrid materials of HSA-Zn(II) complexes at wavelengths corresponding to imine C=N, amide I, and amide II bands. Analysis of secondary structures suggested that including a Zn(II) complex into HSA led to the structural change of HSA, resulting in a more fragile structure than the original HSA. The result was one of the characteristic features of vibrational excitation of IR-FEL in contrast to electronic excitation by UV or visible light.
Highlights
Against long wavelength UVA light up to about 400 nm, contrary to zinc oxides [1], certain Schiff base Zn(II) complexes incorporating amino acid derivative moiety are expected to have applications for use in sunscreens because they can absorb UVA light [2], preventing UVA light from reaching the skin and potentially resulting in many ripple effects
Five new Zn(II) complexes were prepared and characterized with common procedures and docking of the Zn(II) complexes into HSA was confirmed with circular dichroism (CD) spectra and the GOLD program based on the crystal structure of HSA and the density functional theory (DFT) optimized structures of the Zn(II) complexes
At least IR light of 1652 cm−1 was well absorbed by both ZnAHN and ZnVHN, the IR spectra of HSA+ZnAHN exhibited little difference with that of HSA for the three wavenumbers, while HSA+ZnVHN was damaged much more than HSA based on the remaining ratio of α-helix in HSA, which suggested that including ZnVHN into HSA led to a structural change of HSA, resulting in a more fragile structure
Summary
Against long wavelength UVA light up to about 400 nm, contrary to zinc oxides [1], certain Schiff base Zn(II) complexes incorporating amino acid derivative moiety are expected to have applications for use in sunscreens because they can absorb UVA light [2], preventing UVA light from reaching the skin and potentially resulting in many ripple effects. IR light has been reported to damage skin more seriously than UVA light by impacting collagen in the skin’s deep layer [3] In this way, straightforwardly, one can assume that by absorbing IR light with a sunscreen agent for the IR region, proteins can be protected from serious damages occurring in the skin. An infrared free electron laser (IR-FEL) can decompose aggregated proteins as well as harmful amyloids by excitation of vibrational bands [4,5,6]. This IR-FEL is a synchrotron radiation-based coherent light with tunable wavelength within the mid-infrared region (5–10 μm) and oscillated at pico-second pulses. We prepared hybrid materials of protein (human serum albumin; HSA)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
