1QZN

Crystal Structure Analysis of a type II cohesin domain from the cellulosome of Acetivibrio cellulolyticus

Summary for 1QZN

• Entry DOI: 10.2210/pdb1qzn/pdb
• Descriptor: cellulosomal scaffoldin adaptor protein B (2 entities in total)
• Functional Keywords: keywords: cohesins type ii; cellulosome;, structural protein
• Biological source: Acetivibrio cellulolyticus
• Total number of polymer chains: 1
• Total formula weight: 18459.68

Authors

Frolow, F.,Noach, I.,Rosenheck, S.,Lamed, R.,Qi, X.,Shimon, L.J.W.,Bayer, E.A. (deposition date: 2003-09-17, release date: 2004-09-21, Last modification date: 2024-04-03)

Primary citation

Noach, I.,Frolow, F.,Jakoby, H.,Rosenheck, S.,Shimon, L.W.,Lamed, R.,Bayer, E.A.
Crystal structure of a type-II cohesin module from the Bacteroides cellulosolvens cellulosome reveals novel and distinctive secondary structural elements.
J.Mol.Biol., 348:1-12, 2005

PubMed Abstract: The incorporation of enzymes into the multi-enzyme cellulosome complex and its anchoring to the bacterial cell surface are dictated by a set of binding interactions between two complementary protein modules: the cohesin and the dockerin. In this work, the X-ray crystal structure of a type-II cohesin from scaffoldin A of Bacteroides cellulosolvens has been determined to a resolution of 1.6 angstroms using molecular replacement. The type-II B. cellulosolvens cohesin (Bc-cohesin-II) is the first detailed description of a crystal structure for a type-II cohesin, and its features were compared with the known type-I cohesins from Clostridium thermocellum and Clostridium cellulolyticum (Ct-cohesin-I and Cc-cohesin-I, respectively). The overall jelly-roll topology of the type-II Bc-cohesin is very similar to that observed for the type-I cohesins with three additional secondary structures: an alpha-helix and two "beta-flaps" that disrupt the normal course of a beta-strand. In addition, beta-strand 5 is elevated by approximately 4 angstroms on the surface of the molecule, relative to the type-I Ct and Cc-cohesins. Like its type-I analogue, the hydrophobic/aromatic core of Bc-cohesin-II comprises an upper and lower core, but an additional aromatic patch and conserved tryptophan at the crown of the molecule serves to stabilize the alpha-helix of the type-II cohesin. Comparison of Bc-cohesin-II with the known type-I cohesin-dockerin heterodimer suggests that each of the additional secondary structural elements assumes a flanking position relative to the putative dockerin-binding surface. The raised ridge formed by beta-strand 5 confers additional distinctive topographic features to the proposed binding interface that collectively distinguish between the type-II and type-I cohesins.

PubMed: 15808849
DOI: 10.1016/j.jmb.2005.02.024

Experimental method

X-RAY DIFFRACTION (1.9 Å)