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The elasticity of single kettin molecules using a two‐bead laser‐tweezers assay
Author(s) -
Leake Mark C.,
Wilson David,
Bullard Belinda,
Simmons Robert M.
Publication year - 2003
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)03857-7
Subject(s) - optical tweezers , elasticity (physics) , sarcomere , molecule , chemistry , biophysics , titin , stiffness , nanotechnology , materials science , optics , physics , composite material , biology , microbiology and biotechnology , organic chemistry , myocyte
Kettin is a high molecular mass protein of insect muscle associated with thin filaments and α‐actinin in the Z‐disc. It is thought to form a link between thin and thick filaments towards its C‐terminus, contributing significantly to passive sarcomere stiffness. Here the elastic properties were characterised by mechanical stretches on an antibody‐delimited region of the single molecule using two independent optical traps capable of exerting forces up to 150 pN. Step‐like events were observed in the force–extension relationships consistent with the unfolding of Ig domains at moderate force and refolding of these domains at significantly higher forces than have been observed for related modular proteins.