Non-contact current transfer induces the formation and improves the X-ray diffraction quality of protein crystals

The effect of non-contact current transfer on the crystallization of three model proteins (hen egg white lysozyme, bovine pancreatic ribonuclease A, and human recombinant insulin) was investigated using a prototype ion-generator device. The device can produce an equivalent of microcurrent that can be transmitted in a contactless manner by spraying negatively charged ions and using available air gases (O₂) as a transfer medium. From a crystallographic perspective, non-contact current transfer technology clearly enhanced the crystal formation process of these three proteins, as evidenced by the high crystallization speed and crystal quality. The quality and X-ray diffraction patterns of lysozyme crystals grown in the presence and absence of the devices microcurrent were analyzed. Our results indicate a significant positive effect on the quality of the X-ray diffraction pattern after non-contact current transfer, highlighting the value of this technique in protein crystallization.