Crystal structure of uncleaved ovalbumin at 1.95 A resolution.
Stein, P.E., Leslie, A.G., Finch, J.T., Carrell, R.W.(1991) J Mol Biol 221: 941-959
- PubMed: 1942038 
- DOI: https://doi.org/10.1016/0022-2836(91)80185-w
- Primary Citation of Related Structures:  
1OVA - PubMed Abstract: 
Ovalbumin, the major protein in avian egg-white, is a non-inhibitory member of the serine protease inhibitor (serpin) superfamily. The crystal structure of uncleaved, hen ovalbumin was solved by the molecular replacement method using the structure of plakalbumin, a proteolytically cleaved form of ovalbumin, as a starting model. The final refined model, including four ovalbumin molecules, 678 water molecules and a single metal ion, has a crystallographic R-factor of 17.4% for all reflections between 6.0 and 1.95 A resolution. The root-mean-square deviation from ideal values in bond lengths is 0.02 A and in bond angles is 2.9 degrees. This is the first crystal structure of a member of the serpin family in an uncleaved form. Surprisingly, the peptide that is homologous to the reactive centre of inhibitory serpins adopts an alpha-helical conformation. The implications for the mechanism of inhibition of the inhibitory members of the family is discussed.
Organizational Affiliation: 
Department of Haematology, University of Cambridge, U.K.