Eur. Phys. J. B (2015) 88 : 8
https://doi.org/10.1140/epjb/e2014-50717-8

Regular Article

Conformational changes and metastable states induced in proteins by green light

¹ Interdisciplinary Research Group, Romanian Academy, 010071 Bucharest, Romania
² Institute of Atomic Physics, 76900 Magurele, Romania
³ Fundeni Clinical Institute, 010071 Bucharest, Romania
⁴ Materials and Multifunctional Structures, National Institute of Material Physics, 76900 Magurele, Romania
⁵ Department of Chemical Physics, Polytechnic University, 010071 Bucharest, Romania
⁶ Department of Theoretical Physics, Institute of Atomic Physics, 76900 Magurele, Romania

^a e-mail: silv@infim.ro

Received: 15 October 2014
Received in final form: 11 November 2014
Published online: 8 January 2015

Abstract

In this paper we report conformational changes recorded on a protein molecule (α-amylase) under green light irradiation. In order to explain the experimental results we advanced the hypothesis that green light induces electric dipoles in the protein, which interact with each other, generating conformational modifications toward a more compact design, with different physical properties. The experiments were carried out with un-polarized light (λ = 520 nm) from a light-emitting-diode (1000 lm, 20 W, 105 mW on the target). In view of the character of our hypothesis, and corroborated with all our experimental results, we suggest that this phenomenon may be more extended and general, specific for a larger class of proteins, occurring on the protein macromolecules under the green light. The effects of α-amylase protein irradiation were revealed by circular dichroism, fluorescence, Raman and FTIR-spectroscopies, zeta potential, cyclic voltammetry, electric impedance spectroscopy and atomic force microscopy. Tentatively, we term the novel conformations as P^∗ (polarized) proteins.