Open AccessCrystallization and preliminary crystallographic analysis of Mycoplasma arthritidis ‐derived mitogen complexed with peptide/MHC class II antigen
Author(s) -
Zhao Yiwei,
Li Zhong,
Drozd Sandra,
Guo Yi,
Stack Robert,
Hauer Charles,
Li Hongmin
Publication year - 2004
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s090744490302763x
Subject(s) - crystallization , major histocompatibility complex , crystallography , ammonium sulfate , chemistry , antigen , molecular replacement , biology , immunology , chromatography , organic chemistry
Mycoplasma arthritidis ‐derived mitogen (MAM), a bacterial superantigen, has been crystallized in complex with its human receptor, major histocompatibility complex (MHC) class II antigen, by the hanging‐drop vapor‐diffusion method. Crystals were obtained under three conditions, with ammonium sulfate, phosphate salt and PEG 8000 as the precipitant. The crystals grown under these conditions all belong to space group I 222, with the same unit‐cell parameters: a = 137.4, b = 178.2, c = 179.6 Å. Diffraction data were collected to 3.3 and 3.4 Å resolution from crystals of native and selenomethionylated MAM–MHC complexes, respectively. Self‐ and cross‐rotation function calculations suggest the presence of two complex molecules in the asymmetric unit, resulting in a V M of 4.0 and a solvent content of 69%. An interpretable electron‐density map was produced using a combination of molecular replacement and SAD phasing.