Molecular contortionism – on the physical limits of serpin ‘loop-sheet’ polymers
-
James A. Huntington
Abstract
Members of the serpin (serine protease inhibitor) superfamily fold into a metastable conformation that is crucial for proper function. As a consequence, serpins are susceptible to mutations that cause misfolding and the intracellular accumulation of pathogenic polymers. The mechanism of serpin polymerisation remains to be resolved, however, over the past two decades the ‘loop-sheet’ hypothesis has gained wide acceptance. In this mechanism the reactive centre loop of one serpin monomer inserts into the β-sheet A of another (in trans), in a manner similar to what is seen for reactive centre loop-cleaved and latent conformations (in cis). The hypothesis has been refined in response to certain experimental data, but it has proved difficult to assess the various propositions without creating molecular models. Here we evaluate the loop-sheet mechanism by creating models of pentamers of the archetypal serpin α1-antitrypsin. We conclude that an inescapable consequence of the loop-sheet mechanism is polymer compaction and rigidity, properties that are inconsistent with the ‘beads-on-a-string’ morphology of polymers obtained from human tissue. The recent crystal structure of a domain-swapped serpin dimer suggests an alternative mechanism that is consistent with known polymer properties, including the requirement of partial unfolding to induce polymer formation in vitro, and polymerisation from a folding intermediate in vivo.
©2010 by Walter de Gruyter Berlin New York
Artikel in diesem Heft
- Guest Editorial
- Highlight: The Biology of Proteolytic Systems
- Highlight: 6th General Meeting of the International Proteolysis Society
- Structure, mechanism and inhibition of γ-secretase and presenilin-like proteases
- Is BACE1 a suitable therapeutic target for the treatment of Alzheimer's disease? Current strategies and future directions
- Pharmacogenetic features of cathepsin B inhibitors that improve memory deficit and reduce β-amyloid related to Alzheimer's disease
- Proteases in lymphocyte killer function: redundancy, polymorphism and questions remaining
- Pseudo-active sites of protease domains: HGF/Met and Sonic hedgehog signaling in cancer
- Proteolysis of platelet receptors in humans and other species
- Blunting the knife: development of vaccines targeting digestive proteases of blood-feeding helminth parasites
- Impaired turnover of autophagolysosomes in cathepsin L deficiency
- Nuclear cysteine cathepsin variants in thyroid carcinoma cells
- Deletion of cathepsin H perturbs angiogenic switching, vascularization and growth of tumors in a mouse model of pancreatic islet cell cancer
- Cathepsin E enhances anticancer activity of doxorubicin on human prostate cancer cells showing resistance to TRAIL-mediated apoptosis
- Hydrophilic residues surrounding the S1 and S2 pockets contribute to dimerisation and catalysis in human dipeptidyl peptidase 8 (DP8)
- Molecular contortionism – on the physical limits of serpin ‘loop-sheet’ polymers
- The substrate specificity profile of human granzyme A
- Use of granzyme B-based fluorescent protein reporters to monitor granzyme distribution and granule integrity in live cells
Artikel in diesem Heft
- Guest Editorial
- Highlight: The Biology of Proteolytic Systems
- Highlight: 6th General Meeting of the International Proteolysis Society
- Structure, mechanism and inhibition of γ-secretase and presenilin-like proteases
- Is BACE1 a suitable therapeutic target for the treatment of Alzheimer's disease? Current strategies and future directions
- Pharmacogenetic features of cathepsin B inhibitors that improve memory deficit and reduce β-amyloid related to Alzheimer's disease
- Proteases in lymphocyte killer function: redundancy, polymorphism and questions remaining
- Pseudo-active sites of protease domains: HGF/Met and Sonic hedgehog signaling in cancer
- Proteolysis of platelet receptors in humans and other species
- Blunting the knife: development of vaccines targeting digestive proteases of blood-feeding helminth parasites
- Impaired turnover of autophagolysosomes in cathepsin L deficiency
- Nuclear cysteine cathepsin variants in thyroid carcinoma cells
- Deletion of cathepsin H perturbs angiogenic switching, vascularization and growth of tumors in a mouse model of pancreatic islet cell cancer
- Cathepsin E enhances anticancer activity of doxorubicin on human prostate cancer cells showing resistance to TRAIL-mediated apoptosis
- Hydrophilic residues surrounding the S1 and S2 pockets contribute to dimerisation and catalysis in human dipeptidyl peptidase 8 (DP8)
- Molecular contortionism – on the physical limits of serpin ‘loop-sheet’ polymers
- The substrate specificity profile of human granzyme A
- Use of granzyme B-based fluorescent protein reporters to monitor granzyme distribution and granule integrity in live cells
