TY - JOUR
T1 - Importance of the release of strand 1C to the polymerization mechanism of inhibitory serpins
AU - Chang, Wun Shaing W.
AU - Whisstock, James
AU - Hopkins, Paul C.R.
AU - Lesk, Arthur M.
AU - Carrell, Robin W.
AU - Wardell, Mark R.
PY - 1997/1
Y1 - 1997/1
N2 - Serpin polymerization is the underlying cause of several diseases, including thromboembolism, emphysema, liver cirrhosis, and angioedema. Understanding the structure of the polymers and the mechanism of polymerization is necessary to support rational design of therapeutic agents. Here we show that polymerization of antithrombin is sensitive to the addition of synthetic peptides that interact with the structure. A 12-mer peptide (homologous to P14-P3 of antithrombin reactive loop), representing the entire length of s4A, prevented polymerization totally. A 6-mer peptide (homologous to P14 P9 of antithrombin) not only allowed polymerization to occur, but induced it. This effect could be blocked by the addition of a 5- mer peptide with the sic sequence of antithrombin or by an unrelated peptide representing residues 26-31 of cholecystokinin. The s1C or cholecystokinin peptide alone was unable to form a complex with native antithrombin. Moreover, an active antitrypsin double mutant, Pro 361 → Cys, Ser 283 → Cys, was engineered for the purpose of forming a disulfide bond between s1C and s2C to prevent movement of s1C. This mutant was resistant to polymerization if the disulfide bridge was intact, but, under reducing conditions, it regained the potential to polymerize. We have also modeled long-chain serpin polymers with acceptable stereochemistry using two previously proposed loop-A-sheet and loop-C-sheet polymerization mechanisms and have shown both to be sterically feasible, as are 'mixed' linear polymers. We therefore conclude that the release of strand 1C must be an element of the mechanism of serpin polymerization.
AB - Serpin polymerization is the underlying cause of several diseases, including thromboembolism, emphysema, liver cirrhosis, and angioedema. Understanding the structure of the polymers and the mechanism of polymerization is necessary to support rational design of therapeutic agents. Here we show that polymerization of antithrombin is sensitive to the addition of synthetic peptides that interact with the structure. A 12-mer peptide (homologous to P14-P3 of antithrombin reactive loop), representing the entire length of s4A, prevented polymerization totally. A 6-mer peptide (homologous to P14 P9 of antithrombin) not only allowed polymerization to occur, but induced it. This effect could be blocked by the addition of a 5- mer peptide with the sic sequence of antithrombin or by an unrelated peptide representing residues 26-31 of cholecystokinin. The s1C or cholecystokinin peptide alone was unable to form a complex with native antithrombin. Moreover, an active antitrypsin double mutant, Pro 361 → Cys, Ser 283 → Cys, was engineered for the purpose of forming a disulfide bond between s1C and s2C to prevent movement of s1C. This mutant was resistant to polymerization if the disulfide bridge was intact, but, under reducing conditions, it regained the potential to polymerize. We have also modeled long-chain serpin polymers with acceptable stereochemistry using two previously proposed loop-A-sheet and loop-C-sheet polymerization mechanisms and have shown both to be sterically feasible, as are 'mixed' linear polymers. We therefore conclude that the release of strand 1C must be an element of the mechanism of serpin polymerization.
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U2 - 10.1002/pro.5560060110
DO - 10.1002/pro.5560060110
M3 - Article
C2 - 9007980
AN - SCOPUS:0031033206
SN - 0961-8368
VL - 6
SP - 89
EP - 98
JO - Protein Science
JF - Protein Science
IS - 1
ER -