This special Physics department colloquium is scheduled for Thursday 4\/30\/15 at 4:00 pm in Room 135. Coffee, tea and cookies are served at 3:45 pm in the same room. Anyone is welcome.<\/p>\n
Uncovering the nano-mechanics of giant muscle protein titin using a novel single molecule approach<\/strong> Current theories of muscle contraction propose that the power of stroke of a myosin motor is the sole source of mechanical energy driving the sliding filaments of a contracting muscle. These models exclude titin, the largest protein in the human body, which determines the passive elasticity of muscle tissue. Using a technique developed during my postdoctoral training based on a combination of Halo Tag covalent attachment and magnetic tweezers, we have discovered that titin Ig domains from the elastic I band region undergo unfolding\/folding reactions at physiological forces of 6-8 pN. The spontaneous folding contraction can take place at forces below 10 pN, delivering up to 105 zJ of additional contractile energy, a value larger than the mechanical energy delivered by the power stroke of a myosin motor. Based on hour-long recording of single multidomain proteins investigated under force-clamp condition, we have demonstrated a new approach of the construction of the free energy of a protein under force, which includes the physics of extending the polypeptide. The experimental and theoretical advances that I will present strongly suggest the need for the addition of a new force-generating element, titin, to the actomyosin theory of muscle contraction and provide a more realistic modeling for tissue elasticity. Fully deciphering how proteins operate in vivo<\/em> under force will be a critical area of research as this may provide key insights into developing new theories for muscular dystrophy, cancer or misfolding diseases. <\/p>\n","protected":false},"excerpt":{"rendered":" This special Physics department colloquium is scheduled for Thursday 4\/30\/15 at 4:00 pm in Room 135. Coffee, tea and cookies are served at 3:45 pm in the same room. Anyone is welcome. Uncovering the nano-mechanics of giant muscle protein titin …<\/p>\n","protected":false},"author":63,"featured_media":0,"template":"","meta":{"_acf_changed":false,"_tribe_events_status":"","_tribe_events_status_reason":"","_tribe_events_is_hybrid":"","_tribe_events_is_virtual":"","_tribe_events_virtual_video_source":"","_tribe_events_virtual_embed_video":"","_tribe_events_virtual_linked_button_text":"","_tribe_events_virtual_linked_button":"","_tribe_events_virtual_show_embed_at":"","_tribe_events_virtual_show_embed_to":[],"_tribe_events_virtual_show_on_event":"","_tribe_events_virtual_show_on_views":"","_tribe_events_virtual_url":"","footnotes":"","uwm_wg_additional_authors":[]},"tags":[],"tribe_events_cat":[58],"class_list":["post-2692","tribe_events","type-tribe_events","status-publish","hentry","tribe_events_cat-physics-colloquia","cat_physics-colloquia"],"yoast_head":"\n
\nDr. Ionel Popa<\/strong>, Postdoctoral Research Scientist, Department of Biological Sciences, Columbia University, New York, NY<\/p>\n