Crystallization and preliminary X-ray diffraction studies of two domains of a bilobed extra-cytoplasmic function sigma factor SigC from Mycobacterium tuberculosis
Expression, purification and preliminary X-ray diffraction studies of the two domains of the sigma factor SigC from M. tuberculosis are reported. Sigma factors are transcription-regulatory proteins that bind to RNA polymerase and facilitate promoter recognition. The so-called extracytoplasmic function sigma factors help a bacterium to respond to environmental conditions. Mycobacterium tuberculosis SigC (σ{sup C}) is an extracytoplasmic sigma factor that is essential for lethality in a mouse model of infection and is conserved in all pathogenic mycobacterial species. This protein consists of two domains that are connected by an ∼25-amino-acid linker. The N-terminal domain contains the σ{sub 2} DNA-binding motif, whereas the σ{sub 4} motif is located in the C-terminal domain. Native σ{sup C} did not yield diffraction-quality crystals. However, two of its domains have been cloned, expressed and crystallized: σ{sub 2}{sup C} (12.3 kDa) and σ{sub c}{sup C} (7.5 kDa). The σ{sub c}{sup C} crystals belong to the hexagonal space group P6{sub 1}, with unit-cell parameters a = b = 85.28, c = 79.63 Å, and native X-ray diffraction data were collected from this domain to 2.7 Å on an in-house X-ray home source. The σ{sub 4}{sup C} crystals belong to the cubic space group F23, with unit-cell parameters a = b = c = 161.21 Å. X-ray diffraction data were collected from this domain to 3.1 Å, also on an in-house X-ray source.
- OSTI ID:
- 22356055
- Journal Information:
- Acta Crystallographica. Section F, Vol. 61, Issue Pt 8; Other Information: PMCID: PMC1952361; PMID: 16511156; PUBLISHER-ID: bw5094; OAI: oai:pubmedcentral.nih.gov:1952361; Copyright (c) International Union of Crystallography 2005; Country of input: International Atomic Energy Agency (IAEA); ISSN 1744-3091
- Country of Publication:
- United Kingdom
- Language:
- English
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