# Magnetic effects of thaumatin crystals; observation of crystal growth by magneto-Archimedes levitation and magnetic orientation

## TL;DR

This paper explores how magnetic fields influence the growth and orientation of thaumatin protein crystals using a special levitation technique.

## Contribution

The study introduces the use of magneto-Archimedes levitation and magnetic orientation for observing thaumatin crystal growth.

## Key findings

- Thaumatin crystals were successfully grown using magnetic levitation with gadolinium chloride.
- Magnetic orientation of the crystals was visualized using a horizontal magnetic field.
- Gadolinium ions did not incorporate into the crystal structure, suggesting minimal impact on crystallization.

## Abstract

We examined the magnetic effect of thaumatin crystals, which are a well known model of protein crystals but which have hardly been studied for that effect. We succeeded in crystallizing thaumatin by magnetic levitation based on the magneto-Archimedes effect by the addition of the paramagnetic substance gadolinium chloride. We also carried out a chronological observation of the levitation process in a superconducting magnet, and visualized the magnetic orientation of the crystals by applying a magnetic field along the horizontal direction. In another major result, we carried out a diffraction experiment and performed a structural analysis of the crystals. We noticed from the results that no electron density from the gadolinium ion could be observed in the crystals. This suggests the possibility that the paramagnetic substance of the aqueous precipitant solution helps only to promote the crystals’ levitation, and has little effect on thaumatin crystallization.