Resolving controversy of unusually high refractive index of a tubulin
1 Institute of Photonics and Electronics, The Czech Academy of Sciences - Prague, Czechia
2 Institute of Molecular Genetics, The Czech Academy of Sciences - Prague, Czechia
Received: 19 October 2016
Accepted: 2 March 2017
The refractive index of a tubulin is an important parameter underlying fundamental electromagnetic and biophysical properties of microtubules – protein fibers essential for several cell functions including cell division. Yet, the only experimental data available in the current literature show values of the tubulin refractive index which are much higher than what the established theories predict based on the weighted contribution of the polarizability of individual amino acids constituting the protein. To resolve this controversy, we report here modeling and rigorous experimental analysis of the refractive index of a purified tubulin dimer. Our experimental data revealed that the refractive index of the tubulin is at wavelength 589 nm and 25 °C, that is much closer to the values predicted by the established theories than what the earlier experimental data provide.
PACS: 87.16.Ka – Filaments, microtubules, their networks, and supramolecular assemblies / 78.20.Ci – Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) / 87.14.E- – Proteins
© EPLA, 2017