title: Purification, crystallization and preliminary crystallographic analysis of human cystathionine β-synthase.
abstract: Human cystathionine β-synthase (CBS) is a pyridoxal-5'-phosphate-dependent hemeprotein, whose catalytic activity is regulated by S-adenosylmethionine. CBS catalyzes the β-replacement reaction of homocysteine (Hcy) with serine to yield cystathionine. CBS is a key regulator of plasma levels of the thrombogenic Hcy and deficiency in CBS is the single most common cause of homocystinuria, an inherited metabolic disorder of sulfur amino acids. The properties of CBS enzymes, such as domain organization, oligomerization degree or regulatory mechanisms, are not conserved across the eukaryotes. The current body of knowledge is insufficient to understand these differences and their impact on CBS function and physiology. To overcome this deficiency, we have addressed the crystallization and preliminary crystallographic analysis of a protein construct (hCBS516-525) that contains the full-length CBS from Homo sapiens (hCBS) and just lacks amino-acid residues 516-525, which are located in a disordered loop. The human enzyme yielded crystals belonging to space group I222, with unit-cell parameters a=124.98, b=136.33, c=169.83 Å and diffracting X-rays to a resolution of 3.0 Å. The crystal structure appears to contain two molecules in the asymmetric unit which presumably correspond to a dimeric form of the enzyme.
authors.affiliation: Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain.
authors.forename: Iker
authors.initials: I
authors.lastname: Oyenarte
authors.forename: Tomas
authors.initials: T
authors.lastname: Majtan
authors.forename: June
authors.initials: J
authors.lastname: Ereño
authors.forename: María Angeles
authors.initials: MA
authors.lastname: Corral-Rodríguez
authors.forename: Jan P
authors.initials: JP
authors.lastname: Kraus
authors.forename: Luis Alfonso
authors.initials: LA
authors.lastname: Martínez-Cruz
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D003460:Crystallization; D018360:Crystallography, X-Ray; D003541:Cystathionine beta-Synthase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D003541:Cystathionine beta-Synthase