Expression, limited proteolysis and preliminary crystallographic analysis of IpaD, a component of the Shigella flexneri type III secretion system
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford (United Kingdom)
- Department of Molecular Biosciences, University of Kansas (United States)
- Sir William Dunn School of Pathology, University of Oxford (United Kingdom)
IpaD, the putative needle-tip protein of the S. flexneri type III secretion system, has been crystallized in a variety of crystal forms using in-drop proteolysis. Native and selenomethionine-labelled data collection and preliminary analyses are reported. IpaD, the putative needle-tip protein of the Shigella flexneri type III secretion system, has been overexpressed and purified. Crystals were grown of the native protein in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 55.9, b = 100.7, c = 112.0 Å, and data were collected to 2.9 Å resolution. Analysis of the native Patterson map revealed a peak at 50% of the origin on the Harker section v = 0.5, suggesting twofold non-crystallographic symmetry parallel to the b crystallographic axis. As attempts to derivatize or grow selenomethionine-labelled protein crystals failed, in-drop proteolysis was used to produce new crystal forms. A trace amount of subtilisin Carlsberg was added to IpaD before sparse-matrix screening, resulting in the production of several new crystal forms. This approach produced SeMet-labelled crystals and diffraction data were collected to 3.2 Å resolution. The SeMet crystals belong to space group C2, with unit-cell parameters a = 139.4, b = 45.0, c = 99.5 Å, β = 107.9°. An anomalous difference Patterson map revealed peaks on the Harker section v = 0, while the self-rotation function indicates the presence of a twofold noncrystallographic symmetry axis, which is consistent with two molecules per asymmetric unit.
- OSTI ID:
- 22355957
- Journal Information:
- Acta Crystallographica. Section F, Vol. 62, Issue Pt 9; Other Information: PMCID: PMC1894744; PMID: 16946465; PUBLISHER-ID: ll5069; OAI: oai:pubmedcentral.nih.gov:1894744; Copyright (c) International Union of Crystallography 2006; This is an open-access article distributed under the terms described at http://journals.iucr.org/services/termsofuse.html.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1744-3091
- Country of Publication:
- United Kingdom
- Language:
- English
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