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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/27820

Title: Dynamic interactions of type I cohesin modules fine-tune the structure of the cellulosome of Clostridium thermocellum
Authors: Barth, Anders
Hendrix, Jelle
Fried, Daniel
Barak, Yoav
Bayer, Edward A.
Lamb, Don C.
Issue Date: 2018
Publisher: NATL ACAD SCIENCES
Citation: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 115(48), p. E11274-E11283
Abstract: Efficient degradation of plant cell walls by selected anaerobic bacteria is performed by large extracellular multienzyme complexes termed cellulosomes. The spatial arrangement within the cellulosome is organized by a protein called scaffoldin, which recruits the cellulolytic subunits through interactions between cohesin modules on the scaffoldin and dockerin modules on the enzymes. Although many structural studies of the individual components of cellulosomal scaffoldins have been performed, the role of interactions between individual cohesin modules and the flexible linker regions between them are still not entirely understood. Here, we report single-molecule measurements using FRET to study the conformational dynamics of a bimodular cohesin segment of the scaffoldin protein CipA of Clostridium thermocellum. We observe compacted structures in solution that persist on the timescale of milliseconds. The compacted conformation is found to be in dynamic equilibrium with an extended state that shows distance fluctuations on the microsecond timescale. Shortening of the intercohesin linker does not destabilize the interactions but reduces the rate of contact formation. Upon addition of dockerin-containing enzymes, an extension of the flexible state is observed, but the cohesin-cohesin interactions persist. Using allatom molecular-dynamics simulations of the system, we further identify possible intercohesin binding modes. Beyond the view of scaffoldin as "beads on a string," we propose that cohesincohesin interactions are an important factor for the precise spatial arrangement of the enzymatic subunits in the cellulosome that leads to the high catalytic synergy in these assemblies and should be considered when designing cellulosomes for industrial applications.
Notes: [Barth, Anders; Hendrix, Jelle; Lamb, Don C.] Ludwig Maximilians Univ Munchen, Dept Chem, Phys Chem, D-81377 Munich, Germany. [Barth, Anders; Hendrix, Jelle; Lamb, Don C.] Ludwig Maximilians Univ Munchen, Ctr Integrated Prot Sci Munich, D-81377 Munich, Germany. [Barth, Anders; Hendrix, Jelle; Lamb, Don C.] Ludwig Maximilians Univ Munchen, Nanosyst Initat Munich, D-81377 Munich, Germany. [Barth, Anders; Hendrix, Jelle; Lamb, Don C.] Ludwig Maximilians Univ Munchen, Ctr Nanosci, D-81377 Munich, Germany. [Fried, Daniel; Barak, Yoav; Bayer, Edward A.] Weizmann Inst Sci, Dept Biomol Sci, IL-7610001 Rehovot, Israel. [Hendrix, Jelle] Hasselt Univ, Dynam Bioimaging Lab, Adv Opt Microscopy Ctr, B-3590 Diepenbeek, Belgium. [Hendrix, Jelle] Hasselt Univ, Biomed Res Inst, B-3590 Diepenbeek, Belgium. [Fried, Daniel] St Peters Univ, Dept Chem, Jersey City, NJ 07306 USA. [Barak, Yoav] Weizmann Inst Sci, Dept Chem Res Support, IL-7610001 Rehovot, Israel.
URI: http://hdl.handle.net/1942/27820
DOI: 10.1073/pnas.1809283115
ISI #: 000451351000014
ISSN: 0027-8424
Category: A1
Type: Journal Contribution
Appears in Collections: Research publications

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