title: Expression of a selenomethionyl derivative and preliminary crystallographic studies of human cystatin C.
abstract: Human cystatin C, a protein with amyloidogenic properties and a potent inhibitor of papain-like mammalian proteases, has been produced in its full-length form by recombinant techniques and crystallized in two polymorphic forms: cubic and tetragonal. A selenomethionyl derivative of the protein, obtained by Escherichia coli expression and with complete Met-->Se-Met substitution confirmed by mass spectrometry, amino-acid analysis and X-ray absorption spectra, was crystallized in the cubic form. A truncated variant of the protein, lacking ten N-terminal residues, has also been crystallized. The crystals of this variant are tetragonal and, like the two polymorphs of the full-length protein, contain multiple copies of the molecule in the asymmetric unit, suggesting oligomerization of the protein.
authors.affiliation: Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Kozak
authors.forename: E
authors.initials: E
authors.lastname: Jankowska
authors.forename: R
authors.initials: R
authors.lastname: Janowski
authors.forename: Z
authors.initials: Z
authors.lastname: Grzonka
authors.forename: A
authors.initials: A
authors.lastname: Grubb
authors.forename: M
authors.initials: M
authors.lastname: Alvarez Fernandez
authors.forename: M
authors.initials: M
authors.lastname: Abrahamson
authors.forename: M
authors.initials: M
authors.lastname: Jaskolski
mesh_terms: D000595:Amino Acid Sequence; D003460:Crystallization; D018360:Crystallography, X-Ray; D055316:Cystatin C; D015891:Cystatins / Q000737:chemistry* / Q000235:genetics; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry*; D004926:Escherichia coli; D006801:Humans; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D012645:Selenomethionine / Q000737:chemistry*; D051140:Selenoproteins
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D011506:Proteins; D011994:Recombinant Proteins; D051140:Selenoproteins; D012645:Selenomethionine