January 16, 1991 - January 16, 2024

  • Date:14ThursdayJanuary 2021

    ‘Identification of Dynamic Components in the Liquid-Liquid Phase Separation of CPEB4 by EPR Spectroscopy’

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    Time
    09:30 - 10:30
    Lecturer
    Dr. Manas Seal
    Dept Chemical and Biological Physics, WIS
    Organizer
    Department of Materials and Interfaces
    The Helen and Martin Kimmel Institute for Magnetic Resonance
    Contact
    AbstractShow full text abstract about Link: https://weizmann.zoom.us/j/96046369379?pwd=emp0U0wwcm...»
    Link: https://weizmann.zoom.us/j/96046369379?pwd=emp0U0wwcmpNQlhsMisrNmp0bjRDdz09
    Passcode: 693143


    The molecular mechanisms and associated structures and dynamics of liquid-liquid phase separation (LLPS) proteins that form membrane-less organelles in cells have attracted considerable interest in recent years. EPR spectroscopy along with site directed spin labelling (SDSL) using nitroxide spin labels is a well-established technique to study dynamics of proteins. In this seminar I will discuss the dynamic properties of the spin labelled low complexity N-terminal domain of cytoplasmic polyadenylation element binding-4 protein (CPEB4NTD) in its LLPS and non-LLPS states. We found the coexistence of three CPEB4NTD populations with distinct spin label rotational correlation times before and after LLPS. We identified population I as the predominant protein species in the dilute phase, with fast motions that agree with expected dynamic properties of monomeric CPEB4NTD. We assigned population III to a compact ensemble that undergo slow motions, and population II to a looser ensemble experiencing intermediate motions. LLPS, which took place with increasing temperature is associated with increased population of II at the expense of III, while population I remains constant. At the end based on these findings, I will present a three-component equilibrium model that postulates the existence of LLPS-competent CPEB4NTD species (II and III) prior to macroscopic phase separation.
    Lecture