4B97

Biomass sensing modules from putative Rsgi-like proteins of Clostridium thermocellum resemble family 3 carbohydrate-binding module of cellulosome

Summary for 4B97

• Entry DOI: 10.2210/pdb4b97/pdb
• Related: 4B96
• Descriptor: CELLULOSE BINDING DOMAIN-CONTAINING PROTEIN, CALCIUM ION (3 entities in total)
• Functional Keywords: sugar binding protein, biomass sensoring system
• Biological source: CLOSTRIDIUM THERMOCELLUM
• Total number of polymer chains: 1
• Total formula weight: 17304.03

Authors

Yaniv, O.,Fichman, G.,Shimon, L.J.W.,Bayer, E.A.,Lamed, R.,Frolow, F. (deposition date: 2012-09-03, release date: 2013-09-11, Last modification date: 2023-12-20)

Primary citation

Yaniv, O.,Fichman, G.,Borovok, I.,Shoham, Y.,Bayer, E.A.,Lamed, R.,Shimon, L.J.W.,Frolow, F.
Fine-Structural Variance of Family 3 Carbohydrate-Binding Modules as Extracellular Biomass-Sensing Components of Clostridium Thermocellum Anti-Sigma(I) Factors.
Acta Crystallogr.,Sect.D, 70:522-, 2014

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.

PubMed: 24531486
DOI: 10.1107/S139900471302926X

Experimental method

X-RAY DIFFRACTION (1.276 Å)