2ZF9

Crystal structure of a type III cohesin module from the cellulosomal ScaE cell-surface anchoring scaffoldin of Ruminococcus flavefaciens

Summary for 2ZF9

• Entry DOI: 10.2210/pdb2zf9/pdb
• Related: 1ANU 1AOH 1G1K 1OHZ 1TYJ 1ZV9 2B59 2BM3
• Descriptor: ScaE cell-surface anchored scaffoldin protein, GLYCEROL, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: dockerin-binding module, anchoring module, alpha helix, beta flaps, structural protein
• Biological source: Ruminococcus flavefaciens
• Total number of polymer chains: 4
• Total formula weight: 84298.26

Authors

Frolow, F.,Bayer, E.,Alber, O. (deposition date: 2007-12-26, release date: 2008-12-30, Last modification date: 2024-10-30)

Primary citation

Alber, O.,Noach, I.,Rincon, M.T.,Flint, H.J.,Shimon, L.J.W.,Lamed, R.,Frolow, F.,Bayer, E.A.
Cohesin diversity revealed by the crystal structure of the anchoring cohesin from Ruminococcus flavefaciens.
Proteins, 77:699-709, 2009

PubMed Abstract: The cellulosome is an intriguing multienzyme complex found in cellulolytic bacteria that plays a key role in the degradation of plant cell-wall polysaccharides. In Ruminococcus flavefaciens, a predominant fiber-degrading bacterium found in ruminants, the cellulosome is anchored to the bacterial cell wall through a relatively short ScaE scaffoldin. Determination of the crystal structure of the lone type-III ScaE cohesin from R. flavefaciens (Rf-CohE) was initiated as a part of a structural effort to define cellulosome assembly. The structure was determined at 1.95 A resolution by single-wavelength anomalous diffraction. This is the first detailed description of a crystal structure for a type-III cohesin, and its features were compared with those of the known type-I and type-II cohesin structures. The Rf-CohE module folds into a nine-stranded beta-sandwich with jellyroll topology, typically observed for cohesins, and includes two beta-flaps in the midst of beta-strands 4 and 8, similar to the type-II cohesin structures. However, the presence in Rf-CohE of an additional 13-residue alpha-helix located between beta-strands 8 and 9 represents a dramatic divergence from other known cohesin structures. The prominent alpha-helix is enveloped by an extensive N-terminal loop, not observed in any other known cohesin, which embraces the helix presumably enhancing its stability. A planar surface at the upper portion of the front face of the molecule, bordered by beta-flap 8, exhibits plausible dimensions and exposed amino acid residues to accommodate the dockerin-binding site.

PubMed: 19544570
DOI: 10.1002/prot.22483

Experimental method

X-RAY DIFFRACTION (1.95 Å)