Preliminary X-ray diffraction analysis of the cytoplasmic N-terminal domain of the Na/HCO{sub 3} cotransporter NBCe1-A
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520 (United States)
The N-terminal, cytoplasmic domain of the Na{sup +}-coupled HCO{sub 3} cotransporter NBCe1-A crystallizes in the trigonal space group P3{sub 1}21 or P3{sub 1} with pseudo P3{sub 1}21 symmetry and diffracts X-rays to 3.0 Å resolution. The crystal packing demonstrates a domain-swap mechanism for dimerization. The N-terminal cytoplasmic domain of the Na{sup +}-coupled HCO cotransporter NBCe1-A (NtNBCe1) has been linked with proximal renal tubular acidosis. In a previous purification study of recombinant NtNBCe1, crystal growth at a suboptimal protein concentration (<1 mg ml{sup −1}) yielded small single diamond-shaped crystals that diffracted poorly. In the present study, by increasing the protein concentration 50-fold, the crystal size was doubled and robustness was also improved. Crystal annealing made the crystals suitable for X-ray diffraction. The crystals either belong to space group P3{sub 1}21 or P3{sub 1} with pseudo P3{sub 1}21 symmetry, with unit-cell parameters a = 51.7, b = 51.7, c = 200.6 Å, α = β = 90, γ = 120°, and diffract X-rays to 3.0 Å resolution. The calculated Matthews number is 1.9 Å{sup 3} Da{sup −1}, with two monomers of molecular weight ∼83 kDa in the asymmetric unit. The molecular- replacement packing solution shows that the molecules form dimers by a domain-swapping mechanism.
- OSTI ID:
- 22360230
- Journal Information:
- Acta Crystallographica. Section F, Vol. 62, Issue Pt 6; Other Information: PMCID: PMC2243095; PMID: 16754974; PUBLISHER-ID: hc5002; OAI: oai:pubmedcentral.nih.gov:2243095; Copyright (c) International Union of Crystallography 2006; Country of input: International Atomic Energy Agency (IAEA); ISSN 1744-3091
- Country of Publication:
- United Kingdom
- Language:
- English
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