Nature 347, 99 - 102 (06 September 1990); doi:10.1038/347099a0

Crystal structure of ovalbumin as a model for the reactive centre of serpins

Penelope E. Stein^*, Andrew G. W. Leslie^†, John T. Finch^†, William G. Turnell^†, Paul J. McLaughlin^† & Robin W. Carrell^*

^*Department of Haematology, University of Cambridge, Hills Road, Cambridge CB2 2QH, UK
^†MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK

THE serpins are a widely distributed family of proteins with diverse functions; they include the key serine protease inhibitors of human plasma as well as noninhibitory homologues such as hormone-binding globulins, angiotensinogen and egg-white ovalbumin¹. Sequence alignment based on the crystal structure of the cleaved form of the archetypal serpin, a ₁-antitrypsin², indicates that the serpins share a common highly ordered structure³. On cleavage of the reactive centre peptide bond, they characteristically undergo a remarkable conformational change, the newly generated C ter-minus moving some 70 Å to the opposite pole of the molecule. The structure of this post-cleavage form is known, but the conformation of the intact serpins and in particular that of their reactive centre is not. Wright et al.'s structure of plakalbumin⁴ (ovalbumin cleaved by subtilisin) has provided evidence for the conformational change that results from cleavage. We have now determined the structure of native ovalbumin to 1.95 Å resolution and have found that the intact peptide loop forming the analogue to the reactive centre of the inhibitory serpins takes the unexpected form of a protruding, isolated helix. This model of the intact structures of the serpins suggests how they may interact with their target proteases.

References

1.	Hunt, L. T. & Dayhoff, M. O. Biochem. biophys. Res. Commun. 95, 864−871 (1980). | Article | PubMed | ISI | ChemPort |
2.	Löebermann, H., Tokuoka, R., Deisenhofer, J. & Huber, R. J. molec. Biol. 177, 531−556 (1984). | Article | PubMed | ISI | ChemPort |
3.	Huber, R. & Carrell, R. W. Biochemistry 28, 8951−8966 (1989). | Article | PubMed | ISI | ChemPort |
4.	Wright, H. T., Qian, H. X. & Huber, R. J. molec. Biol. 213, 513−518 (1990). | PubMed | ISI | ChemPort |
5.	Carrell, R. W. & Owen, M. C. Nature 317, 730−732 (1985). | Article | PubMed | ISI | ChemPort |
6.	Pemberton, P. A., Stein, P. E., Pepys, M. B., Potter, J. M. & Carrell, R. W. Nature 336, 257−258 (1988). | Article | PubMed | ISI | ChemPort |
7.	Gettins, P. J. biol. Chem. 264, 3781−3785 (1989). | PubMed | ISI | ChemPort |
8.	Stein, P. E., Tewkesbury, D. A. & Carrell, R. W. Biochem. J. 262, 103−107 (1989). | PubMed | ISI | ChemPort |
9.	Linderstrøm-Lang, K. & Ottesen, M. C. r. Trav. Lab. Carlsberg 26, 403−442 (1949).
10.	Wright, H. T. J. biol. Chem. 259, 14335−14336 (l984).
11.	Perry, D. J. & Carrell, R. W. Molec. Biol. Med. 6, 239−243 (1989). | PubMed | ChemPort |
12.	Levy, N. X., Ramesh, N., Cicardi, M., Harrison, R. A. & Davis, A. E. Proc. natn. Acad. Sci. U.S.A. 87, 265−268 (1990). | ChemPort |
13.	McPhalen, C. A. & James, M. N. G. Biochemistry 26, 261−269 (1987). | Article | PubMed | ISI | ChemPort |
14.	Bode, W., Papamokos, E., Musil, D., Seemueller, U. & Fritz, H. EMBO J. 5, 813−818 (1986). | PubMed | ISI | ChemPort |
15.	Ptitsyn, O. B. Pure Appl. Chem. 31, 227−244 (1972). | PubMed | ChemPort |
16.	Warner, R. C. in The Proteins Vol. 2a (eds Neurath, H. & Bailey, K.) 435−485 (Academic, New York, 1954).
17.	Goux, W. J. & Venkatasoubramanian, P. N. Biochemistry 25, 84−94 (1986). | Article | PubMed | ChemPort |
18.	Miller, M., Weinstein, J. N. & Wlodawer, A. J. biol. Chem. 258, 5864−5866 (1983). | PubMed | ChemPort |
19.	Sussmann, J. L., Holbrook, S. R., Church, G. M. & Kim, S.-H. Acta crystallogr. A33, 800−804 (1977).
20.	Brünger, A. T., Kuriyan, J. & Karplus, M. Science 235, 458−460 (1987). | ISI |
21.	Hendrickson, W. A. & Konnert, J. H. in Computing in Crystallography (eds Diamond, R., Ramaseshan, S. & Venkatesan, K.) 13.01−13.23 (Indian Institute of Science, Bangalore, 1980). | ChemPort |
22.	Jones, T. A., J. appl. Crystallogr. 11, 268−272 (1978). | Article | ChemPort |