2PAM

Structure of a H49N, H51N double mutant dTDP-4-keto-6-deoxy-D-glucose-3,4-ketoisomerase from Aneurinibacillus thermoaerophilus complexed with TDP

Summary for 2PAM

• Entry DOI: 10.2210/pdb2pam/pdb
• Related: 2PA7 2PAE 2PAK
• Descriptor: DTDP-6-deoxy-3,4-keto-hexulose isomerase, THYMIDINE-5'-DIPHOSPHATE (3 entities in total)
• Functional Keywords: deoxysugar biosynthesis, s-layer biosynthesis, ketoisomerase, isomerase
• Biological source: Aneurinibacillus thermoaerophilus
• Total number of polymer chains: 2
• Total formula weight: 33225.30

Authors

Davis, M.L.,Thoden, J.B.,Holden, H.M. (deposition date: 2007-03-27, release date: 2007-04-24, Last modification date: 2023-08-30)

Primary citation

Davis, M.L.,Thoden, J.B.,Holden, H.M.
The X-ray Structure of dTDP-4-Keto-6-deoxy-D-glucose-3,4-ketoisomerase.
J.Biol.Chem., 282:19227-19236, 2007

PubMed Abstract: The repeating unit of the glycan chain in the S-layer of the bacterium Aneurinibacillus thermoaerophilus L420-91(T) is composed of four alpha-d-rhamnose molecules and two 3-acetamido-3,6-dideoxy-alpha-d-galactose moieties (abbreviated as Fucp3NAc). Formation of the glycan layer requires nucleotide-activated sugars as the donor molecules. Whereas the enzymes involved in the synthesis of GDP-rhamnose have been well characterized, less is known regarding the structures and enzymatic mechanisms of the enzymes required for the production of dTDP-Fucp3NAc. One of the enzymes involved in the biosynthesis of dTDP-Fucp3NAc is a 3,4-ketoisomerase, hereafter referred to as FdtA. Here we describe the first three-dimensional structure of this sugar isomerase complexed with dTDP and solved to 1.5 A resolution. The FdtA dimer assumes an almost jellyfish-like appearance with the sole alpha-helices representing the tentacles. Formation of the FdtA dimer represents a classical example of domain swapping whereby beta-strands 2 and 3 from one subunit form part of a beta-sheet in the second subunit. The active site architecture of FdtA is characterized by a cluster of three histidine residues, two of which, His(49) and His(51), appear to be strictly conserved in the amino acid sequences deposited to date. Site-directed mutagenesis experiments, enzymatic assays, and x-ray crystallographic analyses suggest that His(49) functions as an active site base.

PubMed: 17459872
DOI: 10.1074/jbc.M702529200

Experimental method

X-RAY DIFFRACTION (2.5 Å)