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Conformational diseases are caused by a structural rearrangement within a protein that results in aberrant intermolecular linkage and tissue deposition. This is typified by the polymers that form with the Z deficiency variant of α[sub 1]-antitrypsin (Glu-342 → Lys). These polymers are retained within hepatocytes to form inclusions that are associated with hepatitis, cirrhosis, and hepatocellular carcinoma. We have assessed a surface hydrophobic cavity in α[sub 1]-antitrypsin as a potential target for rational drug design in order to prevent polymer formation and the associated liver disease. The introduction of either Thr-114 → Phe or Gly-117 → Phe on strand 2 of β-sheet A within this cavity significantly raised the melting temperature and retarded polymer formation. Conversely, Leu-100 → Phe on helix D accelerated polyruer formation, but this effect was abrogated by the addition of Thr-114 → Phe. None of these mutations affected the inhibitory activity of α[sub 1]-antitrypsin. The importance of these observations was underscored by the finding that the Thr-114 → Phe mutation reduced polymer formation and increased the secretion of Z α[sub 1]antitrypsin from a Xenopus oocyte expression system. Moreover cysteine mutants within the hydrophobic pocket were able to bind a range of fluorophores illustrating the accessibility of the cavity to external agents. These results demonstrate the importance of this cavity as a site for drug design to ameliorate polymerization and prevent the associated conformational disease. [ABSTRACT FROM AUTHOR]

Focuses on the characterization of Necrotic (Nec), the necrotic protein that regulates the toll-mediated immune response in drosophila. Results of biochemical analysis; Data showing that Nec is likely to inhibit a range of proteases in Drosophila and that Nec has the specificity requirements to act as the physiological inhibitor of Persophone in vivo.