2XCI: Membrane-embedded monofunctional glycosyltransferase WaaA of Aquifex aeolicus, substrate-free form

Citation:
Abstract
WaaA is a key enzyme in the biosynthesis of LPS, a critical component of the outer envelope of Gram-negative bacteria. Embedded in the cytoplasmic face of the inner membrane, WaaA catalyzes the transfer of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) to the lipid A precursor of LPS. Here we present crystal structures of the free and CMP-bound forms of WaaA from Aquifex aeolicus, an ancient Gram-negative hyperthermophile. These structures reveal details of the CMP-binding site and implicate a unique sequence motif (GGS/TX(5)GXNXLE) in Kdo binding. In addition, a cluster of highly conserved amino acid residues was identified which represents the potential membrane-attachment and acceptor-substrate binding site of WaaA. A series of site-directed mutagenesis experiments revealed critical roles for glycine 30 and glutamate 31 in Kdo transfer. Our results provide the structural basis of a critical reaction in LPS biosynthesis and allowed the development of a detailed model of the catalytic mechanism of WaaA.
PDB ID: 2XCIDownload
MMDB ID: 90379
PDB Deposition Date: 2010/4/26
Updated in MMDB: 2012/05
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 2XCI: monomeric; determined by author and by software (PISA)
Molecular Components in 2XCI
Label Count Molecule
Protein (1 molecule)
1
3-deoxy-d-manno-2-octulosonic Acid Transferase(Gene symbol: kdtA)
Molecule annotation
Chemicals (14 molecules)
1
3
2
6
3
2
4
2
5
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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