Conformational change in elastase following complexation with alpha1-proteinase inhibitor: a CD investigation.
The CD spectrum of porcine pancreatic elastase in complex with alpha1-proteinase inhibitor (alpha1-PI) was calculated by subtracting the CD spectrum of the proteolytically cleaved inhibitor from that of the elastase-alpha1-PI complex. Elastase undergoes a moderate secondary structure change: its beta-structure is partially disordered while its alpha-helix content is poorly affected. In contrast, its tertiary structure undergoes a significant structural loosening upon complexation. These alterations have been compared with those following chemical and thermal unfolding of free elastase. Inhibitor-bound elastase and the denaturation intermediate of free elastase share secondary but not tertiary structural features. On the other hand, both free and complexed elastases undergo a single-step transition in tertiary structure upon thermal unfolding. These data are discussed in terms of the inhibition and structural modification of elastase induced by alpha1-PI observed by previous investigators.
Bousquet
Jean-Alain
JA
CNRS UMR 7034, Université Louis Pasteur de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67400 Illkirch, France. bousquet@pharma.u-strasbg.fr
Duranton
Jérôme
J
Mély
Yves
Y
Bieth
Joseph G
JG
D002942:Circular Dichroism; D010196:Pancreatic Elastase / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D013816:Thermodynamics; D000515:alpha 1-Antitrypsin / Q000378:metabolism*
D000515:alpha 1-Antitrypsin; D010196:Pancreatic Elastase