Expression of the Majastridin-like protein from Streptococcus pneumonia for crystallization and antibody production

Abstract: The F1 part of F0F1-ATP synthase in the proteobacterium Rhodobacter blasticus contains five different proteins, but when the DNA was sequenced a sixth gene was found in the operon. The protein that corresponds to the sixth gene has been named Majastridin. When an amino acid BLAST search is performed with the Majastridin sequence, protein sequences have been found that are similar to Majastridin in other bacterial strains, and one of them is Streptococcus pneumonia. The hypothetical protein from Streptococcus pneumonia contains 242 amino acids and has a molecular weight around 30 kDa.   In this work the Majastridin-like protein from Streptococcus pneumonia was expressed in E. coli cells and purified with nickel affinity chromatography and size exclusion chromatography. The result was verified with SDS-PAGE and western blot. The purified protein was then crystallized with the hanging drop method, where crystals were formed and optimization was made. The protein was also used to produce antibodies.