Download MendeleyArabinose 5-phosphate covalently inhibits transaldolase.
Light, S.H., Anderson, W.F.(2014) J Struct Funct Genomics 15: 41-44
- PubMed: 24510200
- DOI: https://doi.org/10.1007/s10969-014-9174-1
- Primary Citation of Related Structures:
3UPB - PubMed Abstract:
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.
Organizational Affiliation:
Center for Structural Genomics of Infectious Diseases, Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
