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The F‐helix of serpins plays an essential, active role in the proteinase inhibition mechanism
Author(s) -
Gettins Peter G.W
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)02924-1
Subject(s) - serpin , mechanism (biology) , proteinase 3 , helix (gastropod) , chemistry , biochemistry , biophysics , biology , genetics , epistemology , snail , antibody , gene , autoantibody , ecology , philosophy
Proteinase inhibition by serpins requires a 70 Å translocation of the proteinase, circumvention of the blocking helix F, and a crushing of the proteinase to render it catalytically incompetent. I propose that temporary displacement of the F‐helix during proteinase transit, and its subsequent return after complete passage of the proteinase, not only allows the proteinase to reach its final location, but provides an absolutely essential coupling mechanism for making the final proteinase crushing step energetically favorable. The F‐helix is therefore not a passive impediment to proteinase translocation, but a critical, active element in permitting the serpin inhibition mechanism to operate successfully.