title: Structure determination of quinoprotein methylamine dehydrogenase from Thiobacillus versutus.
abstract: The crystal structure of quinoprotein methylamine dehydrogenase from Thiobacillus versutus (EC 1.4.99.3, Mr = 123,500) has been solved to 2.25 A resolution. The crystals of space group P3(1)21 (a = b = 129.8, c = 104.3 A) contain half a tetrameric enzyme molecule in the asymmetric unit, with a solvent content of ca 70%. The procedure used to solve this structure involved multiple isomorphous-replacement phasing, complemented by phase extension using solvent flattening, and phase combination with partial-model phases. The use of solvent flattening was essential to generate good quality electron density maps into which initial models were built. These partial models were refined using molecular-dynamics procedures. Refined model phases were then combined with solvent-flattening phases to generate improved electron density distributions. In the absence of an amino-acid sequence for this enzyme, the current 2.25 A resolution electron density map was interpreted to provide a model for the complete molecule. The crystallographic R factor for this model, which lacks any water molecules, is 28.6% for data between 6.0 and 2.25 A resolution.
authors.affiliation: Department of Chemistry, University of Groningen, The Netherlands.
authors.forename: F M
authors.initials: FM
authors.lastname: Vellieux
authors.forename: K H
authors.initials: KH
authors.lastname: Kalk
authors.forename: J
authors.initials: J
authors.lastname: Drenth
authors.forename: W G
authors.initials: WG
authors.lastname: Hol
mesh_terms: D000595:Amino Acid Sequence; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004220:Disulfides / Q000737:chemistry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry*; D011487:Protein Conformation; D012997:Solvents; D013855:Thiobacillus / Q000201:enzymology*; D014961:X-Ray Diffraction
chemical_list: D004220:Disulfides; D012997:Solvents; C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors