title: The elasticity of single kettin molecules using a two-bead laser-tweezers assay.
abstract: 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.
authors.affiliation: 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
authors.forename: Mark C
authors.initials: MC
authors.lastname: Leake
authors.forename: David
authors.initials: D
authors.lastname: Wilson
authors.forename: Belinda
authors.initials: B
authors.lastname: Bullard
authors.forename: Robert M
authors.initials: RM
authors.lastname: Simmons
mesh_terms: 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
chemical_list: D064211:Connectin; D029721:Drosophila Proteins; D019476:Insect Proteins; D009124:Muscle Proteins; C577347:sls protein, Drosophila