Cloning, expression, purification, crystallization and preliminary X-ray crystallographic study of molybdopterin...

Thermus thermophilus is a Gram-negative aerobic thermophilic eubacterium which can grow at temperatures ranging from 323 to 355 K. In addition to their importance in thermostability or adaptation strategies for survival at high temperatures, the thermostable enzymes in thermophilic organisms contribute to a wide range of biotechnological applications. The molybdenum cofactor in all three kingdoms consists of a tricyclic pyranopterin termed molybdopterin that bears the cis-dithiolene group responsible for molybdenum ligation. The crystals of molybdopterin synthase from T. thermophilus HB8 belong to the primitive monoclinic space group P2(1), with unit-cell parameters a = 33.94, b = 103.32, c = 59.59 A, beta = 101.3 degrees. Preliminary studies and molecular-replacement calculations reveal the presence of three monomers in the asymmetric unit.