3UPB image
Deposition Date 2011-11-17
Release Date 2011-11-30
Last Version Date 2024-11-06
Entry Detail
PDB ID:
3UPB
Keywords:
Title:
1.5 Angstrom Resolution Crystal Structure of Transaldolase from Francisella tularensis in Covalent Complex with Arabinose-5-Phosphate
Biological Source:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.50 Å
R-Value Free:
0.17
R-Value Work:
0.15
R-Value Observed:
0.15
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Transaldolase
Gene (Uniprot):talA
Chain IDs:A, B
Chain Length:345
Number of Molecules:2
Biological Source:Francisella tularensis subsp. tularensis
Primary Citation
Arabinose 5-phosphate covalently inhibits transaldolase.
J.Struct.Funct.Genom. 15 41 44 (2014)
PMID: 24510200 DOI: 10.1007/s10969-014-9174-1

Abstact

Arabinose 5-phosphate (A5P) is the aldopentose version of the ketohexose fructose 6-phosphate (F6P), having identical stereochemistry but lacking atoms corresponding to the 1-carbon and 1-hydroxyl. Despite structural similarity and conservation of the reactive portion of F6P, F6P acts as a substrate whereas A5P is reported to be an inhibitor of transaldolase. To address the lack of A5P reactivity we determined a crystal structure of the Francisella tularensis transaldolase in complex with A5P. This structure reveals that like F6P, A5P forms a covalent Schiff base with active site Lys135. Unlike F6P, A5P binding fails to displace an ordered active site water molecule. Retaining this water necessitates conformational changes at the A5P-protein linkage that possibly hinder reactivity. The findings presented here show the basis of A5P inhibition and suggest an unusual mechanism of competitive, reversible-covalent transaldolase regulation.

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