3K8L

Crystal structure of SusG-D498N mutant with maltoheptaose

Summary for 3K8L

• Entry DOI: 10.2210/pdb3k8l/pdb
• Related: 3K8K 3K8M
• Related PRD ID: PRD_900030 PRD_900035
• Descriptor: Alpha-amylase, susG, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-beta-D-glucopyranose, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, ... (7 entities in total)
• Functional Keywords: amylase, alpha8/beta8 barrel, cbm, beta-sandwich, membrane protein
• Biological source: Bacteroides thetaiotaomicron
• Cellular location: Cell outer membrane ; Lipid-anchor : Q8A1G3
• Total number of polymer chains: 2
• Total formula weight: 156813.37

Authors

Koropatkin, N.M.,Smith, T.J. (deposition date: 2009-10-14, release date: 2010-03-02, Last modification date: 2023-09-06)

Primary citation

Koropatkin, N.M.,Smith, T.J.
SusG: A Unique Cell-Membrane-Associated alpha-Amylase from a Prominent Human Gut Symbiont Targets Complex Starch Molecules.
Structure, 18:200-215, 2010

PubMed Abstract: SusG is an alpha-amylase and part of a large protein complex on the outer surface of the bacterial cell and plays a major role in carbohydrate acquisition by the animal gut microbiota. Presented here, the atomic structure of SusG has an unusual extended, bilobed structure composed of amylase at one end and an unprecedented internal carbohydrate-binding motif at the other. Structural studies further demonstrate that the carbohydrate-binding motif binds maltooligosaccharide distal to, and on the opposite side of, the amylase catalytic site. SusG has an additional starch-binding site on the amylase domain immediately adjacent to the active cleft. Mutagenesis analysis demonstrates that these two additional starch-binding sites appear to play a role in catabolism of insoluble starch. However, elimination of these sites has only a limited effect, suggesting that they may have a more important role in product exchange with other Sus components.

PubMed: 20159465
DOI: 10.1016/j.str.2009.12.010

Experimental method

X-RAY DIFFRACTION (2.3 Å)