title: A hydrophobic pocket in the active site of glycolytic aldolase mediates interactions with Wiskott-Aldrich syndrome protein.
abstract: Aldolase plays essential catalytic roles in glycolysis and gluconeogenesis. However, aldolase is a highly abundant protein that is remarkably promiscuous in its interactions with other cellular proteins. In particular, aldolase binds to highly acidic amino acid sequences, including the C terminus of the Wiskott-Aldrich syndrome protein, an actin nucleation-promoting factor. Here we report the crystal structure of tetrameric rabbit muscle aldolase in complex with a C-terminal peptide of Wiskott-Aldrich syndrome protein. Aldolase recognizes a short, four-residue DEWD motif (residues 498-501), which adopts a loose hairpin turn that folds around the central aromatic residue, enabling its tryptophan side chain to fit into a hydrophobic pocket in the active site of aldolase. The flanking acidic residues in this binding motif provide further interactions with conserved aldolase active site residues Arg-42 and Arg-303, aligning their side chains and forming the sides of the hydrophobic pocket. The binding of Wiskott-Aldrich syndrome protein to aldolase precludes intramolecular interactions of its C terminus with its active site and is competitive with substrate as well as with binding by actin and cortactin. Finally, based on this structure, a novel naphthol phosphate-based inhibitor of aldolase was identified, and its structure in complex with aldolase demonstrated mimicry of the Wiskott-Aldrich syndrome protein-aldolase interaction. The data support a model whereby aldolase exists in distinct forms that regulate glycolysis or actin dynamics.
authors.affiliation: Department of Biochemistry, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Miguel
authors.initials: M
authors.lastname: St-Jean
authors.forename: Tina
authors.initials: T
authors.lastname: Izard
authors.forename: Jurgen
authors.initials: J
authors.lastname: Sygusch
mesh_terms: D000818:Animals; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry* / Q000378:metabolism*; D006019:Glycolysis; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D009132:Muscles / Q000201:enzymology*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D051316:Wiskott-Aldrich Syndrome Protein / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D011994:Recombinant Proteins; D051316:Wiskott-Aldrich Syndrome Protein; D005634:Fructose-Bisphosphate Aldolase