In: Chemistry
How do we get crystals of protein by various methods?
Proteins are dissolved in an aqueous environment and sample solution until they reach a supersaturated state during the crystallisation process.There are various methods to get this supersaturated state.
1. Vapour Diffusion - Droplets containing purified protein, buffer, and precipitant equilibrate with a bigger reservoir containing identical buffers and precipitants at higher concentrations in this approach. The precipitant and protein concentrations in the droplet of protein solution are initially low, but as the drop and reservoir equilibrate, the precipitant and protein concentrations in the drop grow. Crystal growth happens in the droplet if the correct crystallisation solutions are employed for a certain protein.
2. Microbatch- This technique usually involves immersing of very small volume of protein droplet in oil.
3. Microdialysis- In this technique the sample is separated from the crystallization reagent via way of means of a semi-permeable membrane. The semi-permeable membrane lets in small molecules, together with salts, additives, and different crystallization reagents to pass, however prevents organic macromolecules from crossing the membrane.
4. Free-Interface Diffusion - This method brings collectively protein and precipitation solutions with out premixing them, however instead, injecting them via both facets of a channel, permitting equilibrium via diffusion. The solutions come into touch in a reagent chamber, each at their most concentrations, beginning spontaneous nucleation. As the system comes into equilibrium, the extent of supersaturation decreases, favouring crystal growth.
Various methods include -