Duplicated Dockerin Subdomains of <i>Clostridium thermocellum</i> Endoglucanase CelD Bind to a Cohesin Domain of the Scaffolding Protein CipA with Distinct Thermodynamic Parameters and a Negative Cooperativity

Schaeffer, Francis; Matuschek, Markus; Guglielmi, Gérard; Miras, Isabelle; Alzari, Pedro M.; Béguin, Pierre

doi:10.1021/bi011853m

Cited by 72 publications

(83 citation statements)

References 41 publications

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“…Although a previous study showed that the Coh-Doc interaction, between 25 and 50°C, was both enthalpically and entropically favorable, there was a linear relationship between the increase in temperature and a decrease in both enthalpy and entropy. Extrapolation of the data of Schaeffer et al (24) to 65°C would also have generated negative entropic and enthalpic values and a K a of 2.5 ϫ 10 7 , Ϸ40ϫ greater than for the Xyn-10B dockerin-cohesin 2 interaction. Recent data by other groups have also indicated that the affinity of different Type I Coh-Doc interactions can vary between pairs.…”

Section: Resultsmentioning

confidence: 96%

“…Recent site-directed mutagenesis studies on the seventh cohesin domain of C. thermocellum CipA (24,27) propose that residues Asp-39, Tyr-74, and Glu-86 and Gly-89 of this domain play a key role in the formation of Coh-Doc complexes and cohesin-cohesin dimers (27). The crystal structure of the CohDoc complex reveals that the equivalent residues in cohesin 2, Asp-39A, Tyr-74A, and Glu-86A, respectively, do indeed interact with the dockerin.…”

Section: Resultsmentioning

confidence: 99%

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Cellulosome assembly revealed by the crystal structure of the cohesin–dockerin complex

Carvalho

Dias

Prates

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

235

311

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The utilization of organized supramolecular assemblies to exploit the synergistic interactions afforded by close proximity, both for enzymatic synthesis and for the degradation of recalcitrant substrates, is an emerging theme in cellular biology. Anaerobic bacteria harness a multiprotein complex, termed the ''cellulosome,'' for efficient degradation of the plant cell wall. This megadalton catalytic machine organizes an enzymatic consortium on a multifaceted molecular scaffold whose ''cohesin'' domains interact with corresponding ''dockerin'' domains of the enzymes. Here we report the structure of the cohesin-dockerin complex from Clostridium thermocellum at 2.2-Å resolution. The data show that the ␤-sheet cohesin domain interacts predominantly with one of the helices of the dockerin. Whereas the structure of the cohesin remains essentially unchanged, the loop-helix-helix-loop-helix motif of the dockerin undergoes conformational change and ordering compared with its solution structure, although the classical 12-residue EF-hand coordination to two calcium ions is maintained. Significantly, internal sequence duplication within the dockerin is manifested in near-perfect internal twofold symmetry, suggesting that both ''halves'' of the dockerin may interact with cohesins in a similar manner, thus providing a higher level of structure to the cellulosome and possibly explaining the presence of ''polycellulosomes.'' The structure provides an explanation for the lack of cross-species recognition between cohesin-dockerin pairs and thus provides a blueprint for the rational design, construction, and exploitation of these catalytic assemblies.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Cellulosome assembly revealed by the crystal structure of the cohesin–dockerin complex

Carvalho

Dias

Prates

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

235

311

View full text Add to dashboard Cite

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“…The equivalent residues in the WT dockerin; Asn-44B, Thr-49B, Ser-52B and Arg-23B (N 2), respectively, do not make direct interactions with the cohesin (SI Table 5). Mutagenesis studies support the importance of the polar interactions between the cohesin residues Ala-36A, Asn-37A, Asp-39A, Tyr-74A, Glu-86A, Gly-89A and Glu-131A (26,27) and type I dockerins, although the functional significance of Arg-77A, which seems to make important hydrogen bonds with Arg-23B and Arg-57B at the C-terminal end of the two dockerin binding sites, has not previously been explored.…”

Section: Resultsmentioning

confidence: 99%

“…27 and 30) indicates that both binding sites display similar affinity for the cohesin partner. It is interesting to note that the apparently more polar nature of ligand binding via helix 1 is entropically driven, whereas the more hydrophobic dockerin helix-3 cohesin interaction is associated with a gain in enthalpy (27). Whereas it is currently unclear why the thermodynamic forces driving ligand binding are not reflected in the nature of the amino acids that mediate cohesin-dockerin recognition, the thermodynamic parameters are likely to be influenced by changes in solvation, which cannot easily be explained by static crystal structures.…”

Section: Relative Affinity Of the Two Binding Sites Of The Dockerin Fmentioning

confidence: 99%

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Evidence for a dual binding mode of dockerin modules to cohesins

Carvalho

Dias²,

Nagy

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

126

204

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The assembly of proteins that display complementary activities into macromolecular complexes is critical to cellular function. One such enzyme complex, of environmental significance, is the plant cell wall degrading apparatus of anaerobic bacteria, termed the cellulosome. The complex assembles through the interaction of enzyme-derived ''type I dockerin'' modules with the multiple ''cohesin'' modules of the scaffolding protein. Clostridium thermocellum type I dockerin modules contain a duplicated 22-residue sequence that comprises helix-1 and helix-3, respectively. The crystal structure of a C. thermocellum type I cohesin-dockerin complex showed that cohesin recognition was predominantly through helix-3 of the dockerin. The sequence duplication is reflected in near-perfect 2-fold structural symmetry, suggesting that both repeats could interact with cohesins by a common mechanism in wild-type (WT) proteins. Here, a helix-3 disrupted mutant dockerin is used to visualize the reverse binding in which the dockerin mutant is indeed rotated 180 o relative to the WT dockerin such that helix-1 now dominates recognition of its protein partner. The dual binding mode is predicted to impart significant plasticity into the orientation of the catalytic subunits within this supramolecular assembly, which reflects the challenges presented by the degradation of a heterogeneous, recalcitrant, insoluble substrate by a tethered macromolecular complex.cellulosome structure ͉ cellulosome assembly ͉ Clostridium thermocellum ͉ cohesin-dockerin

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Dockerin Domains

Volkman¹,

Lytle²,

Wu³

2004

Handbook of Metalloproteins

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Bacterial protein domains known as dockerins serve as anchoring or tethering modules for the assembly of large extracellular cellulase complexes called cellulosomes. Dockerins function through interactions with another class of protein‐interaction module, the cohesins, and both domain families are currently divided into two subclasses (type I and type II) originally based on binding specificity. Dockerin sequences contain a pair of 22‐residue motifs with homology to calcium‐binding loops of the EF‐hand family. When exposed to calcium, the dockerin adopts a novel fold distinct from EF‐hand proteins that binds its cognate cohesin with high affinity. Conversely, in the absence of calcium, the dockerin domain is unfolded and does not bind cohesin. Thus, dockerin domains serve as calcium‐regulated mediators of protein complex formation. Analysis of conserved sequence features in the context of the three‐dimensional dockerin structure may identify elements that confer class and species specificity of dockerin–cohesin binding reactions.

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Duplicated Dockerin Subdomains of Clostridium thermocellum Endoglucanase CelD Bind to a Cohesin Domain of the Scaffolding Protein CipA with Distinct Thermodynamic Parameters and a Negative Cooperativity

Cited by 72 publications

References 41 publications

Cellulosome assembly revealed by the crystal structure of the cohesin–dockerin complex

Cellulosome assembly revealed by the crystal structure of the cohesin–dockerin complex

Evidence for a dual binding mode of dockerin modules to cohesins

Dockerin Domains

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