Biomass sensoring module from putative Rsgi2 protein of Clostridium thermocellum resemble family 3 carbohydrate-binding module of cellulosome

Experimental Data Snapshot

  • Resolution: 1.18 Å
  • R-Value Free: 0.150 
  • R-Value Work: 0.124 
  • R-Value Observed: 0.125 

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This is version 1.2 of the entry. See complete history


Fine-Structural Variance of Family 3 Carbohydrate-Binding Modules as Extracellular Biomass-Sensing Components of Clostridium Thermocellum Anti-Sigma(I) Factors.

Yaniv, O.Fichman, G.Borovok, I.Shoham, Y.Bayer, E.A.Lamed, R.Shimon, L.J.W.Frolow, F.

(2014) Acta Crystallogr D Biol Crystallogr 70: 522

  • DOI: https://doi.org/10.1107/S139900471302926X
  • Primary Citation of Related Structures:  
    4B97, 4B9C, 4B9P

  • PubMed Abstract: 

    The anaerobic, thermophilic, cellulosome-producing bacterium Clostridium thermocellum relies on a variety of carbohydrate-active enzymes in order to efficiently break down complex carbohydrates into utilizable simple sugars. The regulation mechanism of the cellulosomal genes was unknown until recently, when genomic analysis revealed a set of putative operons in C. thermocellum that encode σI factors (i.e. alternative σ factors that control specialized regulon activation) and their cognate anti-σI factor (RsgI). These putative anti-σI-factor proteins have modules that are believed to be carbohydrate sensors. Three of these modules were crystallized and their three-dimensional structures were solved. The structures show a high overall degree of sequence and structural similarity to the cellulosomal family 3 carbohydrate-binding modules (CBM3s). The structures of the three carbohydrate sensors (RsgI-CBM3s) and a reference CBM3 are compared in the context of the structural determinants for the specificity of cellulose and complex carbohydrate binding. Fine structural variations among the RsgI-CBM3s appear to result in alternative substrate preferences for each of the sensors.

  • Organizational Affiliation

    Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
TYPE 3A CELLULOSE-BINDING DOMAIN PROTEIN166Acetivibrio thermocellus ATCC 27405Mutation(s): 0 
Gene Names: rsgI2Cthe_0267
Find proteins for A3DC27 (Acetivibrio thermocellus (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372))
Explore A3DC27 
Go to UniProtKB:  A3DC27
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA3DC27
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.18 Å
  • R-Value Free: 0.150 
  • R-Value Work: 0.124 
  • R-Value Observed: 0.125 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 31.736α = 90
b = 62.289β = 90
c = 79.274γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-09-11
    Type: Initial release
  • Version 1.1: 2014-02-12
    Changes: Database references, Source and taxonomy
  • Version 1.2: 2014-02-26
    Changes: Database references