4Q0K

Crystal Structure of Phytohormone Binding Protein from Medicago truncatula in complex with gibberellic acid (GA3)

Replaces:  3US7

Summary for 4Q0K

• Entry DOI: 10.2210/pdb4q0k/pdb
• Related: 1icx 1ifv 1xdf 2flh 2qim 4PSB 4jhg
• Descriptor: PHYTOHORMONE BINDING PROTEIN MTPHBP, GIBBERELLIN A3, GLYCEROL, ... (4 entities in total)
• Functional Keywords: cytokinin-specific binding protein (csbp), pr-10 fold, plant hormone binding, gibberellin, hormone binding protein
• Biological source: Medicago truncatula (Barrel medic)
• Total number of polymer chains: 1
• Total formula weight: 18827.28

Authors

Ciesielska, A.,Barciszewski, J.,Ruszkowski, M.,Jaskolski, M.,Sikorski, M. (deposition date: 2014-04-02, release date: 2014-04-23, Last modification date: 2023-09-20)

Primary citation

Ruszkowski, M.,Sliwiak, J.,Ciesielska, A.,Barciszewski, J.,Sikorski, M.,Jaskolski, M.
Specific binding of gibberellic acid by Cytokinin-Specific Binding Proteins: a new aspect of plant hormone-binding proteins with the PR-10 fold.
Acta Crystallogr.,Sect.D, 70:2032-2041, 2014

PubMed Abstract: Pathogenesis-related proteins of class 10 (PR-10) are a family of plant proteins with the same fold characterized by a large hydrophobic cavity that allows them to bind various ligands, such as phytohormones. A subfamily with only ~20% sequence identity but with a conserved canonical PR-10 fold have previously been recognized as Cytokinin-Specific Binding Proteins (CSBPs), although structurally the binding mode of trans-zeatin (a cytokinin phytohormone) was found to be quite diversified. Here, it is shown that two CSBP orthologues from Medicago truncatula and Vigna radiata bind gibberellic acid (GA3), which is an entirely different phytohormone, in a conserved and highly specific manner. In both cases a single GA3 molecule is found in the internal cavity of the protein. The structural data derived from high-resolution crystal structures are corroborated by isothermal titration calorimetry (ITC), which reveals a much stronger interaction with GA3 than with trans-zeatin and pH dependence of the binding profile. As a conclusion, it is postulated that the CSBP subfamily of plant PR-10 proteins should be more properly linked with general phytohormone-binding properties and termed phytohormone-binding proteins (PhBP).

PubMed: 25004979
DOI: 10.1107/S1399004714010578

Experimental method

X-RAY DIFFRACTION (1.34 Å)