Inhibitory conformation of the reactive loop of alpha 1-antitrypsin.
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Elliott PR, Lomas DA, Carrell RW, Abrahams JP
Inhibitory conformation of the reactive loop of alpha 1-antitrypsin.
Nat Struct Biol. 1996 Aug;3(8):676-81.
- PubMed ID
- 8756325 [ View in PubMed]
- Abstract
The reactive site loop of the serpin family of serine proteinase inhibitors is flexible and can adopt a number of diverse conformations. A 2.9 A resolution structure of alpha 1-antitrypsin-the principal proteinase inhibitor in human plasma-shows the loop in a stable canonical conformation matching that found in all other families of serine proteinase inhibitors. This unexpected finding in the absence of loop insertion into the body of the molecule favours a two-stage mechanism of inhibition and provides a model for the heparin activation of antithrombin. The beta-pleated strand conformation of the loop also accounts for the polymerization of the serpins in disease and for their association with other beta-sheet structures, most notably the beta-amyloid of Alzheimer's disease.