BME Colloquium Series: Matthew J. Lang, Ph.D.

Force-fluorescence measurements of biological parts and motors

Biological Engineering & Mechanical Engineering Massachusetts Institute of Technology Cambridge, MA

Abstract

A general introduction to single molecule methods applied to molecular and cellular systems will be introduced including force spectroscopy of peptide aptamers, actin machinery and amyloid fibers. Detailed studies of two molecular motors will follow: kinesin which transports cargo and ClpXP which recognizes proteins, mechanically unfolds, transports and degrades them. Force generation in the kinesin motor protein is driven by folding between the N-terminal cover strand and neck linker to form the cover neck bundle, a mechanism that is directly tested by optical trapping measurements of engineered kinesin motor mutants. The ClpXP protease, a member of the AAA+ class of motors, destroys protein substrates by coordinating machinery for recognition, denaturation, translocation and degradation, events which are measured a new single-molecule fluorescence assay using a series of fluorescently labeled GFP based substrates.