Abstract
Human extracellular superoxide dismutase (hEC-SOD) is a secreted tetrameric protein involved in protection against oxygen free radicals. Because EC-SOD is too large a protein for structural determination by multidimensional NMR, and attempts to crystallize the protein for X-ray structural determination have failed, the three-dimensional structure of hEC-SOD is unknown. This means that alternative strategies for structural studies are needed. The N-terminal domain of EC-SOD has already been studied using the fusion protein FusNN, comprised of the 49 N-terminal amino acids from hEC-SOD fused to human carbonic anhydrase (HCAII). The N-terminal domain in this fusion protein forms a well-defined three-dimensional structure, which probably contains alpha-helical elements and is responsible for the tetramerization of the protein. In this work, we have extended the studies, using site-directed mutagenesis in combination with size-exclusion chromatography, CD, and fluorescence spectroscopy, to investigate the nature of the tetrameric interaction. Our results show that the hydrophobic side of a predicted amphiphatic alpha-helix (formed by residues 14-32) in the N-terminal domain is essential for the subunit interaction.
Full Text
The Full Text of this article is available as a PDF (3.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Banner D. W., Bloomer A. C., Petsko G. A., Phillips D. C., Pogson C. I., Wilson I. A., Corran P. H., Furth A. J., Milman J. D., Offord R. E. Structure of chicken muscle triose phosphate isomerase determined crystallographically at 2.5 angstrom resolution using amino acid sequence data. Nature. 1975 Jun 19;255(5510):609–614. doi: 10.1038/255609a0. [DOI] [PubMed] [Google Scholar]
- Biesecker G., Harris J. I., Thierry J. C., Walker J. E., Wonacott A. J. Sequence and structure of D-glyceraldehyde 3-phosphate dehydrogenase from Bacillus stearothermophilus. Nature. 1977 Mar 24;266(5600):328–333. doi: 10.1038/266328a0. [DOI] [PubMed] [Google Scholar]
- Blake C. C., Geisow M. J., Oatley S. J., Rérat B., Rérat C. Structure of prealbumin: secondary, tertiary and quaternary interactions determined by Fourier refinement at 1.8 A. J Mol Biol. 1978 May 25;121(3):339–356. doi: 10.1016/0022-2836(78)90368-6. [DOI] [PubMed] [Google Scholar]
- Borgstahl G. E., Parge H. E., Hickey M. J., Beyer W. F., Jr, Hallewell R. A., Tainer J. A. The structure of human mitochondrial manganese superoxide dismutase reveals a novel tetrameric interface of two 4-helix bundles. Cell. 1992 Oct 2;71(1):107–118. doi: 10.1016/0092-8674(92)90270-m. [DOI] [PubMed] [Google Scholar]
- Edlund A., Edlund T., Hjalmarsson K., Marklund S. L., Sandström J., Strömqvist M., Tibell L. A non-glycosylated extracellular superoxide dismutase variant. Biochem J. 1992 Dec 1;288(Pt 2):451–456. doi: 10.1042/bj2880451. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans P. R., Hudson P. J. Structure and control of phosphofructokinase from Bacillus stearothermophilus. Nature. 1979 Jun 7;279(5713):500–504. doi: 10.1038/279500a0. [DOI] [PubMed] [Google Scholar]
- Freskgård P. O., Mårtensson L. G., Jonasson P., Jonsson B. H., Carlsson U. Assignment of the contribution of the tryptophan residues to the circular dichroism spectrum of human carbonic anhydrase II. Biochemistry. 1994 Nov 29;33(47):14281–14288. doi: 10.1021/bi00251a041. [DOI] [PubMed] [Google Scholar]
- Hol W. G., Halie L. M., Sander C. Dipoles of the alpha-helix and beta-sheet: their role in protein folding. Nature. 1981 Dec 10;294(5841):532–536. doi: 10.1038/294532a0. [DOI] [PubMed] [Google Scholar]
- Hol W. G. The role of the alpha-helix dipole in protein function and structure. Prog Biophys Mol Biol. 1985;45(3):149–195. doi: 10.1016/0079-6107(85)90001-x. [DOI] [PubMed] [Google Scholar]
- Jergil B., Ohlsson R. Phosphorylation of proteins in rat liver. Endogenous phosphorylation and dephosphorylation of proteins from smooth and rough endoplasmic reticulum and free ribosomes. Eur J Biochem. 1974 Jul 1;46(1):13–25. doi: 10.1111/j.1432-1033.1974.tb03592.x. [DOI] [PubMed] [Google Scholar]
- Khalifah R. G., Strader D. J., Bryant S. H., Gibson S. M. Carbon-13 nuclear magnetic resonance probe of active-site ionizations in human carbonic anhydrase B. Biochemistry. 1977 May 17;16(10):2241–2247. doi: 10.1021/bi00629a031. [DOI] [PubMed] [Google Scholar]
- Kunkel T. A. Rapid and efficient site-specific mutagenesis without phenotypic selection. Proc Natl Acad Sci U S A. 1985 Jan;82(2):488–492. doi: 10.1073/pnas.82.2.488. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miller S. The structure of interfaces between subunits of dimeric and tetrameric proteins. Protein Eng. 1989 Nov;3(2):77–83. doi: 10.1093/protein/3.2.77. [DOI] [PubMed] [Google Scholar]
- Mårtensson L. G., Jonasson P., Freskgård P. O., Svensson M., Carlsson U., Jonsson B. H. Contribution of individual tryptophan residues to the fluorescence spectrum of native and denatured forms of human carbonic anhydrase II. Biochemistry. 1995 Jan 24;34(3):1011–1021. doi: 10.1021/bi00003a036. [DOI] [PubMed] [Google Scholar]
- O'Shea E. K., Klemm J. D., Kim P. S., Alber T. X-ray structure of the GCN4 leucine zipper, a two-stranded, parallel coiled coil. Science. 1991 Oct 25;254(5031):539–544. doi: 10.1126/science.1948029. [DOI] [PubMed] [Google Scholar]
- RICKLI E. E., GHAZANFAR S. A., GIBBONS B. H., EDSALL J. T. CARBONIC ANHYDRASES FROM HUMAN ERYTHROCYTES. PREPARATION AND PROPERTIES OF TWO ENZYMES. J Biol Chem. 1964 Apr;239:1065–1078. [PubMed] [Google Scholar]
- Reeke G. N., Jr, Becker J. W., Edelman G. M. The covalent and three-dimensional structure of concanavalin A. IV. Atomic coordinates, hydrogen bonding, and quaternary structure. J Biol Chem. 1975 Feb 25;250(4):1525–1547. [PubMed] [Google Scholar]
- Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tainer J. A., Getzoff E. D., Beem K. M., Richardson J. S., Richardson D. C. Determination and analysis of the 2 A-structure of copper, zinc superoxide dismutase. J Mol Biol. 1982 Sep 15;160(2):181–217. doi: 10.1016/0022-2836(82)90174-7. [DOI] [PubMed] [Google Scholar]
- Tibell L. A., Skärfstad E., Jonsson B. H. Determination of the structural role of the N-terminal domain of human extracellular superoxide dismutase by use of protein fusions. Biochim Biophys Acta. 1996 Jan 4;1292(1):47–52. doi: 10.1016/0167-4838(95)00189-1. [DOI] [PubMed] [Google Scholar]
- Tibell L., Hjalmarsson K., Edlund T., Skogman G., Engström A., Marklund S. L. Expression of human extracellular superoxide dismutase in Chinese hamster ovary cells and characterization of the product. Proc Natl Acad Sci U S A. 1987 Oct;84(19):6634–6638. doi: 10.1073/pnas.84.19.6634. [DOI] [PMC free article] [PubMed] [Google Scholar]
