Crystal structure of SusG with acarboseCrystal structure of SusG with acarbose

Structural highlights

3k8m is a 2 chain structure with sequence from Bacteroides thetaiotaomicron. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.5Å
Ligands:, , , , , , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SUSG_BACTN Alpha-amylase that cleaves starch into oligosaccharides before internalization for degradation, the first step in starch degradation.[1] [2] [3]

Evolutionary Conservation

 

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

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.

SusG: a unique cell-membrane-associated alpha-amylase from a prominent human gut symbiont targets complex starch molecules.,Koropatkin NM, Smith TJ Structure. 2010 Feb 10;18(2):200-15. PMID:20159465[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Shipman JA, Cho KH, Siegel HA, Salyers AA. Physiological characterization of SusG, an outer membrane protein essential for starch utilization by Bacteroides thetaiotaomicron. J Bacteriol. 1999 Dec;181(23):7206-11. PMID:10572122
  2. Cho KH, Salyers AA. Biochemical analysis of interactions between outer membrane proteins that contribute to starch utilization by Bacteroides thetaiotaomicron. J Bacteriol. 2001 Dec;183(24):7224-30. PMID:11717282
  3. Koropatkin NM, Smith TJ. SusG: a unique cell-membrane-associated alpha-amylase from a prominent human gut symbiont targets complex starch molecules. Structure. 2010 Feb 10;18(2):200-15. PMID:20159465 doi:10.1016/j.str.2009.12.010
  4. Koropatkin NM, Smith TJ. SusG: a unique cell-membrane-associated alpha-amylase from a prominent human gut symbiont targets complex starch molecules. Structure. 2010 Feb 10;18(2):200-15. PMID:20159465 doi:10.1016/j.str.2009.12.010

3k8m, resolution 2.50Å

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