Study of protein production, folding, crystallization and structure: survival of motor neuron protein and Fenna-Matthews-Olson protein

Protein crystallization has become an extremely important tool in biochemistry since the first structure of the protein Myoglobin was solved in 1958. Survival of motor neuron protein has proved to be an elusive target in regards to producing crystals of sufficient quality for X-ray diffraction. One form of Survival of motor neuron protein has been found to be a cause of the disease Spinal Muscular Atrophy that currently affects 1 in 6000 live births. The production, purification and crystallization of Survival of motor neuron protein are detailed. The Fenna-Matthews-Olson (FMO) protein from Pelodictyon phaeum is responsible for the transfer of energy from the chlorosome complex to the reaction center of the bacteria. The three-dimensional structure of the protein has been solved to a resolution of 2.0Å with the Rwork and Rfree values being 16.6% and 19.9% respectively. This new structure is compared to the FMO protein structures of Prosthecocholoris aestuarii 2K and Chlorobium tepidum. The early structures of FMO contained seven bacteriochlorophyll-a (BChl) molecules but the recent discovery that there is an eighth BChl molecule in Ptc. aestuarii 2K and Cbl. tepidum and now in Pld. phaeum requires that the energy transfer mechanism be reexamined. Simulated spectra are fitted to the experimental optical spectra to determine how the BChl molecules transfer energy through the protein. The inclusion of the eighth BChl molecule within these simulations may have an impact on how energy transfer through FMO can be described. In conclusion, a reliable method of purifying and crystallizing the SMNWT protein is detailed, the placement of the 8th BChl-a within the electron density and the implications on energy transfer within the FMO protein when the 8th BChl-a is included from the green sulfur bacteria Pld. phaeum is discussed.