Open AccessExpression, purification and crystallization of Streptococcus dysgalactiae ‐derived mitogen
Author(s) -
Papageorgiou Anastassios C.,
Saarinen Susanna,
RamirezBartutis Rosa,
Kato Hidehito,
Uchiyama Takehiko,
Kirikae Teruo,
MiyoshiAkiyama Toru
Publication year - 2006
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309106003678
Subject(s) - streptococcus dysgalactiae , superantigen , escherichia coli , microbiology and biotechnology , biology , crystallization , chemistry , streptococcus , bacteria , biochemistry , gene , streptococcus agalactiae , staphylococcus aureus , genetics , organic chemistry
Superantigens are bacterial or viral toxins with potent immunostimulatory properties. Streptococcus dysgalactiae ‐derived mitogen, a 25 kDa protein, is a recently discovered superantigen isolated from S. dysgalactiae culture supernatant. Sequence considerations suggest that it belongs to a new superantigen family distinct from other superantigens. The protein was expressed in Escherichia coli cells and purified to homogeneity. Crystals were grown at pH 4.2–4.4 in the presence of 18–20%( w / v ) PEG 3350 and 0.4 M lithium nitrate. A complete data set to 2.4 Å resolution was collected from a single crystal at liquid‐nitrogen temperatures using synchrotron radiation. The crystals belong to space group P 3/ P 3 1 / P 3 2 , with unit‐cell parameters a = b = 52.7, c = 62.4 Å, γ = 120° and one molecule in the crystallographic asymmetric unit.