For years crystallization has been used to understand and identify the molecular structure of proteins. In order to obtain the best and most useful crystals from a particular protein and to properly identify its structure, it is necessary to purify the protein. The goal of this work is to develop a multi-step purification technique for the purification of two specific proteins, mGO, modified glycolate oxidase, and SL06. This purification aims to isolate the protein from a complex mixture. Each protein is expressed in bacteria, His-Tagged, sonicated, and dialyzed in order to purify. SL06 is a dimeric receptor protein that is involved in the stress response of a tomato. When exposed to abscisic acid, a hormone known to induce plant stress, SL06 forms a complex and is known to exhibit differences in crystal structure. By identifying the crystal structure of SL06 and SL06-ABA complexes, the differences and similarities between the two structures can be examined. mGO, also known as modified glycolate oxidase, is a protein involved in the production of glyoxylate and subsequently oxalate in humans. In people who suffer from hyperoxaluria type 1, AGXT, enzyme acting in the breakdown of oxalate is defective and causes a buildup in oxalate. When mGO reacts with a ligand, CCPST, the crystal structure of mGO is altered and oxalate production is inhibited. By examining the structures of mGO and mGO-CCPST, scientist can identify conformational changes that may aid in the treatment of hyperoxaluria. The use of this simplified multistep process aided in the crystallization process by producing a higher concentration of protein.
Pope, Albryona, "Multi-step Protein Purification Technique for Crystallization" (2013). G-STEM Posters. 19.