Crystal structure of uncleaved ovalbumin at 1.95 A resolution.
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.
Department of Haematology, University of Cambridge, U.K.
P E
PE
Stein
A G
AG
Leslie
J T
JT
Finch
R W
RW
Carrell
D000818:Animals; D002645:Chickens; D002852:Chromatography, Ion Exchange; D003627:Data Interpretation, Statistical; D006860:Hydrogen Bonding; D008670:Metals / Q000737:chemistry; D008958:Models, Molecular; D010047:Ovalbumin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D012997:Solvents; D013696:Temperature; D014961:X-Ray Diffraction; D000515:alpha 1-Antitrypsin / Q000737:chemistry
D008670:Metals; D010446:Peptide Fragments; D012997:Solvents; D000515:alpha 1-Antitrypsin; C038141:plakalbumin; D010047:Ovalbumin