Effect of Neurodegenerative Mutations in the NEFL Gene on Thermal Denaturation of the Neurofilament Light Chain Protein

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Victoria V. Nefedova^1,a*, Daria S. Yampolskaya¹, Sergey Y. Kleymenov^1,2, Natalia A. Chebotareva¹, Alexander M. Matyushenko¹, and Dmitrii I. Levitsky¹

¹Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia

²Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia

^* To whom correspondence should be addressed.

Received January 4, 2023; Revised March 2, 2023; Accepted March 2, 2023

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Effects of E90K, N98S, and A149V mutations in the light chain of neurofilaments (NFL) on the structure and thermal denaturation of the NFL molecule were investigated. By using circular dichroism spectroscopy, it was shown that these mutations did not lead to the changes in α-helical structure of NFL, but they caused noticeable effects on the stability of the molecule. We also identified calorimetric domains in the NFL structure by using differential scanning calorimetry. It was shown that the E90K replacement leads to the disappearance of the low-temperature thermal transition (domain 1). The mutations cause changes in the enthalpy of NFL domains melting, as well as lead to the significant changes in the melting temperatures (T_m) of some calorimetric domains. Thus, despite the fact that all these mutations are associated with the development of Charcot–Marie–Tooth neuropathy, and two of them are even located very close to each other in the coil 1A, they affect differently structure and stability of the NFL molecule.

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KEY WORDS: intermediate filaments, neurofilaments, coiled-coil proteins, circular dichroism spectroscopy, differential scanning calorimetry

DOI: 10.1134/S0006297923050048

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