The Structural Basis of Alpha-Glucan Recognition by a Family 41 Carbohydrate-Binding Module from Therotoga Maritima
Starch recognition by carbohydrate-binding modules (CBMs) is important for the activity of starch-degrading enzymes. The N-terminal family 41 CBM, TmCBM41 (from pullulanase PulA secreted by Thermotoga maritima) was shown to have {alpha}-glucan binding activity with specificity for {alpha}-1, 4-glucans but was able to tolerate the {alpha}-1, 6-linkages found roughly every three or four glucose units in pullulan. Using X-ray crystallography, the structures were solved for TmCBM41 in an uncomplexed form and in complex with maltotetraose and 63-{alpha}-d-glucosyl-maltotriose (GM3). Ligand binding was facilitated by stacking interactions between the {alpha}-faces of the glucose residues and two tryptophan side-chains in the two main subsites of the carbohydrate-binding site. Overall, this mode of starch binding is quite well conserved by other starch-binding modules. The structure in complex with GM3 revealed a third binding subsite with the flexibility to accommodate an {alpha}-1, 4- or an {alpha}-1, 6-linked glucose.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 959750
- Report Number(s):
- BNL-82736-2009-JA; JMOBAK; TRN: US201016%%894
- Journal Information:
- Journal of Molecular Biology, Vol. 365, Issue 3; ISSN 0022-2836
- Country of Publication:
- United States
- Language:
- English
Similar Records
Transcriptional regulation of the carbohydrate utilization network in Thermotoga maritima
Genomic and transcriptomic analysis of carbohydrate utilization by Paenibacillus sp. JDR-2: systems for bioprocessing plant polysaccharides