PUL ID

PUL0217

PubMed

25342756, J Biol Chem. 2014 Dec 12;289(50):34965-77. doi: 10.1074/jbc.M114.579904. Epub 2014 Oct 23.

Characterization method

RNA-Seq

Genomic accession number

NZ_KE386494.1

Nucelotide position range

1052130-1059390

Substrate

galactomannan,glucomannan,glucose,mannose

Loci

CALPO_RS0106040-CALPO_RS0106070

Species

Caldanaerobius polysaccharolyticus/44256

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 555 (-) CDS No
- 674 - 1657 (-) CAZyme: GH130 Yes
- 1691 - 2515 (-) TC: gnl|TC-DB|Q9WYR1|3.A.1.1.39 Yes
- 2545 - 3423 (-) TC: gnl|TC-DB|Q93KC0|3.A.1.1.11 Yes
- 3511 - 4854 (-) TC: gnl|TC-DB|O06989|3.A.1.1.26 Yes
- 5009 - 6025 (-) TF: DBD-Pfam|LacI,DBD-SUPERFAMILY|0036955 Yes
- 6269 - 7261 (-) CAZyme: GH5_36 Yes

PUL ID

PUL0217

PubMed

25342756, J Biol Chem. 2014 Dec 12;289(50):34965-77. doi: 10.1074/jbc.M114.579904. Epub 2014 Oct 23.

Title

Structural and biochemical basis for mannan utilization by Caldanaerobius polysaccharolyticus strain ATCC BAA-17.

Author

Chekan JR, Kwon IH, Agarwal V, Dodd D, Revindran V, Mackie RI, Cann I, Nair SK

Abstract

Hemicelluloses, the polysaccharide component of plant cell walls, represent one of the most abundant biopolymers in nature. The most common hemicellulosic constituents of softwoods, such as conifers and cycads, are mannans consisting of a 1,4-linked beta-mannopyranosyl main chain with branch decorations. Efforts toward the utilization of hemicellulose for bioconversion into cellulosic biofuels have resulted in the identification of several families of glycoside hydrolases that can degrade mannan. However, effective biofermentation of manno-oligosaccharides is limited by a lack of appropriate uptake route in ethanologenic organisms. Here, we used transcriptome sequencing to gain insights into mannan degradation by the thermophilic anaerobic bacterium Caldanaerobius polysaccharolyticus. The most highly up-regulated genes during mannan fermentation occur in a cluster containing several genes encoding enzymes for efficient mannan hydrolysis as well as a solute-binding protein (CpMnBP1) that exhibits specificity for short mannose polymers but exhibited the flexibility to accommodate branched polysaccharide decorations. Co-crystal structures of CpMnBP1 in complex with mannobiose (1.4-A resolution) and mannotriose (2.2-A resolution) revealed the molecular rationale for chain length and oligosaccharide specificity. Calorimetric analysis of several active site variants confirmed the roles of residues critical to the function of CpMnBP1. This work represents the first biochemical characterization of a mannose-specific solute-binding protein and provides a framework for engineering mannan utilization capabilities for microbial fermentation.