Open AccessPurification, crystallization and preliminary crystallographic analysis of human cystathionine β‐synthase
Author(s) -
Oyenarte Iker,
Majtan Tomas,
Ereño June,
CorralRodríguez María Angeles,
Kraus Jan P.,
MartínezCruz Luis Alfonso
Publication year - 2012
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309112037219
Subject(s) - cystathionine beta synthase , pyridoxal phosphate , homocystinuria , serine , chemistry , cystathionine gamma lyase , amino acid , enzyme , biochemistry , crystallization , homocysteine , stereochemistry , crystallography , cysteine , methionine , cofactor , organic chemistry
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 ( h CBS 516–525 ) that contains the full‐length CBS from Homo sapiens ( h CBS) and just lacks amino‐acid residues 516–525, which are located in a disordered loop. The human enzyme yielded crystals belonging to space group I 222, 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.