PDBsum entry 4b9c

Carbohydrate-binding protein

PDB id: 4b9c

Contents

Protein chain

150 a.a.

Metals

_CA

Waters ×167

PDB id:

4b9c

Name:

Carbohydrate-binding protein

Title:

Biomass sensoring modules from putative rsgi-like proteins of clostridium thermocellum resemble family 3 carbohydrate-binding module of cellulosome

Structure:

Type 3a cellulose-binding domain protein. Chain: a. Fragment: family 3b carbohydrate binding module, residues 340-485. Synonym: rsgi1 protein. Engineered: yes

Source:

Clostridium thermocellum. Organism_taxid: 203119. Atcc: 27405. Expressed in: escherichia coli. Expression_system_taxid: 511693. Expression_system_variant: ril.

Resolution:

1.17Å R-factor: 0.170 R-free: 0.185

Authors:

O.Yaniv,L.J.W.Shimon,E.A.Bayer,R.Lamed,F.Frolow

Key ref:

O.Yaniv et al. (2014). Fine-structural variance of family 3 carbohydrate-binding modules as extracellular biomass-sensing components of Clostridium thermocellum anti-σI factors. Acta Crystallogr D Biol Crystallogr, 70, 522-534. PubMed id: 24531486 DOI: 10.1107/S139900471302926X

Date:

04-Sep-12 Release date: 11-Sep-13

Protein chain

A3DBH1  (RSGI1_CLOTH) -  Anti-sigma-I factor RsgI1 from Acetivibrio thermocellus (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372)

Seq: 486 a.a.

Struc: 150 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

DOI no: 10.1107/S139900471302926X

Acta Crystallogr D Biol Crystallogr 70:522-534 (2014)

PubMed id: 24531486

Fine-structural variance of family 3 carbohydrate-binding modules as extracellular biomass-sensing components of Clostridium thermocellum anti-σI factors.

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

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 σ(I) factors (i.e. alternative σ factors that control specialized regulon activation) and their cognate anti-σ(I) factor (RsgI). These putative anti-σ(I)-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.