The elasticity of single kettin molecules using a two-bead laser-tweezers assay.
Kettin is a high molecular mass protein of insect muscle associated with thin filaments and alpha-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.
Leake
Mark C
MC
The Randall Centre for Molecular Mechanisms of Cell Function, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK. m.leake1@physics.oc.ac.uk
Wilson
David
D
Bullard
Belinda
B
Simmons
Robert M
RM
D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D064211:Connectin; D004330:Drosophila; D029721:Drosophila Proteins; D004548:Elasticity / Q000528:radiation effects; D006430:Hemiptera; D007259:Infrared Rays; D019476:Insect Proteins / Q000737:chemistry* / Q000528:radiation effects*; D007834:Lasers; D008954:Models, Biological; D009010:Monte Carlo Method; D009124:Muscle Proteins / Q000737:chemistry* / Q000528:radiation effects*; D017510:Protein Folding; D017434:Protein Structure, Tertiary / Q000502:physiology / Q000528:radiation effects; D013314:Stress, Mechanical
D064211:Connectin; D029721:Drosophila Proteins; D019476:Insect Proteins; D009124:Muscle Proteins; C577347:sls protein, Drosophila