Why do some proteins have multiple crystal types when crystalized?

Why do some proteins have multiple crystal types when crystalized?

Because of the high solvent content, the individual macromolecules in protein crystals are surrounded by layers of water that maintain their structure virtually unchanged from that found in solution. In fact, multiple crystal forms are sometimes seen coexisting in the same sample of mother liquor.

What is multi domain proteins?

In a multidomain protein, each domain may fulfill its own function independently, or in a concerted manner with its neighbours.

What salt is most commonly used for protein crystallization?

Ammonium sulfate is the most widely used precipitant of the salt type. Citrate salts, due to their chelating properties, may be especially useful when the presence of divalent cations interferes with crystallization.

How much protein do you need for crystallization?

10 mg/mL
Few other experiments in biochemistry require as high concentrations of pure protein as crystallization experiments. Crystallization typically requires 10 mg/mL concentration for proteins in the 10-30 kDa range. Larger protein tend to require less concentration (2-5 mg/mL).

Which salt is used for enzyme crystallization?

Sodium malonate clearly was much more successful than any other salt, resulting in the crystallization of 19 of the 23 macromolecules, almost twice as effective as the next most successful salt, which was a draw between sodium acetate, sodium tartrate, sodium formate, and ammonium sulfate (11 of 22).

Why is it difficult to crystallize membrane proteins?

Membrane Proteins. Membrane proteins, which have predominantly hydrophobic surfaces, are hard to crystallize because they tend to aggregate in aqueous solutions. Proteins which have post-translational modifications are also hard to crystallize because the PTMs are usually not uniform among the protein molecules.

Is a motif a domain?

Motif is a certain grouping of the super secondary elements of proteins such as alpha helices and beta structures while domain is the functional unit of a protein. Furthermore, motif is a secondary structure while domain is responsible for the tertiary structure of the protein.

Which is the best method for protein crystallization?

Successes in macromolecular crystallization have multiplied rapidly in recent years owing to the advent of practical, easy-to-use screening kits and the application of laboratory robotics. A brief review will be given here of the most popular methods, some guiding principles and an overview of current technologies.

Who was the first person to crystallize proteins?

In the 1930s Northrop and coworkers purified a number of important enzymes by crystallization, most notably from the pancreas of pigs and cows (reviewed in Northrop et al., 1948▶). A cascade of successes with other enzymes quickly followed, leading to the award of Nobel Prizes to Sumner and Northrop.

How is supersaturation produced in protein crystallization?

Supersaturation is produced through the addition of mild precipitating agents such as neutral salts or polymers, and by the manipulation of various parameters that include temperature, ionic strength and pH.

How did crystallography change the field of molecular biology?

The integration of recombinant DNA technology with X-ray crystallo­graphy subsequently produced a revolution in structural biology that has, in turn, totally transformed the field of molecular biology.