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TY - JOUR AU - Stein, Penelope E. AU - Leslie, Andrew G. W. AU - Finch, John T. AU - Turnell, William G. AU - McLaughlin, Paul J. AU - Carrell, Robin W. PY - 1990 DA - 1990/09/01 TI - Crystal structure of ovalbumin as a model for the reactive centre of serpins JO - Nature SP - 99 EP - 102 VL - 347 IS - 6288 AB - 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 α1-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. SN - 1476-4687 UR - https://doi.org/10.1038/347099a0 DO - 10.1038/347099a0 ID - Stein1990 ER -