The mating type transcription factor MAT1-1-1 from the fungal human pathogen Aspergillus fumigatus: synthesis, purification, and crystallization of the DNA binding domain.

Mating type (MAT) loci are the most important and significant regulators of sexual reproduction and development in ascomycetous fungi. Usually, they encode two transcription factors (TFs), named MAT1-1-1 or MAT1-2-1. Mating-type strains carry only one of the two TF genes, which control expression of pheromone and pheromone receptor genes, involved in the cell-cell recognition process. The present work presents the crystallization for the alpha1 (1) domain of MAT1-1-1 from the human pathogenic fungus Aspergillus fumigatus (AfMAT1-1-1). Crystals were obtained for the complex between a polypeptide containing the 1 domain and DNA carrying the AfMAT1-1-1 recognition sequence. A streak seeding technique was applied to improve native crystal quality, resulting in diffraction data to 3.2 [A] resolution. Further, highly redundant data sets were collected from the crystals of selenomethionine-substituted AfMAT1-1-1 with a maximum resolution of 3.2 [A]. This is the first report of structural studies on the 1 domain MAT regulator involved in the mating of ascomycetes. SynopsisAn optimized purification and crystallization protocol together with initial X-ray datasets are described for this mating type transcription factor from human pathogenic fungus Aspergillus fumigatus.