# On-the-fly resolution enhancement in X-ray protein crystallography using electric field

## TL;DR

This paper shows that applying an electric field after protein crystal formation can improve the resolution of X-ray crystallography results.

## Contribution

The study demonstrates on-the-fly resolution enhancement in X-ray crystallography using a post-crystallization electric field.

## Key findings

- Applying an electric field between 2 and 11 kV/cm improved crystal diffraction quality.
- The protein structure remained largely unperturbed up to a defined electric field threshold.
- Diffraction quality improved progressively with increased exposure time to the electric field.

## Abstract

X-ray crystallography has tremendously served structural biology by routinely providing high-resolution 3D structures of macromolecules. The extent of information encoded in the X-ray crystallography is proportional to which resolution the crystals diffract and the structure can be refined to. Therefore, there is a continuous effort to obtain high-quality crystals, especially for those proteins, which are considered difficult to crystallize into high-quality protein crystals of suitable sizes for X-ray crystallography. Efforts in enhancing the resolution in X-ray crystallography have also been made by optimizing crystallization protocols using external stimuli such as an electric field and magnetic field during the crystallization. Here, we present the feasibility of on-the-fly post-crystallization resolution enhancement of the protein crystal diffraction by applying a high-voltage electric field. The electric field between 2 and 11 kV/cm, which was applied after mounting the crystals in the beamline, resulted in the enhancement of the resolution. The crystal diffraction quality improved progressively with the exposure time. Moreover, we also find that upto defined electric field threshold, the protein structure remains largely unperturbed, a conclusion further supported by molecular dynamics simulations.

The online version contains supplementary material available at 10.1007/s00249-025-01731-5.