CRYSTAL-STRUCTURE OF CLEAVED EQUINE LEUKOCYTE ELASTASE INHIBITOR DETERMINED AT 1.95-ANGSTROM RESOLUTION

The crystal structure of active-site cleaved equine leucocyte elastase inhiitor, a member of the serpin superfamily, has been solved and refined to a crystallographic R-factor of 17·6% at 1·95 Å resolution. Despite being an intracellular inhibitor with rather low sequence homology of 30% to human α1-antichymotrypsin and α1-proteinase inhibitor, the three-dimensional structures are very similar, with deviations only at the sites of insertions and few mobile secondary structure elements. The better resolution in comparison with the structures of other cleaved serpins allows a more precise description of the so-called R-state of the serpins. © 1992.