Subject area	Biology.
More specific subject area	Nanobiotechnology.
Type of data	Tables and images.
How data was acquired	Images were acquired with transmission electron microscope JEOL JEM-2100 (JEOL Ltd.) and size distributions were acquired using dynamic light scattering method with Zetasizer Nano ZS analyzer (Malvern Instruments, Ltd.).
Data format	Raw and analyzed.
Experimental factors	Magnetite nanoparticles were synthesized by coprecipitation of iron salts FeCl2and FeCl3and stabilized with the fusion protein of Barstar and C-term part of Mms6 protein in concentrations ranging from 0.3 µM to 40 µM.
Experimental features	The nanoparticle properties were studied by transmission electron microscopy and dynamic light scattering.
Data source location	Moscow, Russia.
Data accessibility	All data are presented in this article.