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Updated: Mar 12, 2026
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X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
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Metallohydrolase biomimetics with catalytic and structural flexibility.
Luisa L Mendes1, Daniel Englert2, Christiane Fernandes1
1Laboratório de Ciências Químicas, Universidade Estadual do Norte Fluminense, 28013-602, Campos dos Goytacazes/RJ, Brazil. adolfo@uenf.br.
Dalton Transactions (Cambridge, England : 2003)
|November 3, 2016
Summary
The dinuclear zinc complex with HTPDP ligand is more effective at hydrolyzing bis(2,4-dinitrophenyl)phosphate (BDNPP) than the tetranuclear complex with HTPPNOL ligand. Compound 1 efficiently breaks down BDNPP, while compound 3 shows limited activity and an unusual reaction pathway.
Area of Science:
- Coordination Chemistry
- Bioinorganic Chemistry
- Catalysis
Background:
- Nitrogen-rich polydentate ligands are crucial in coordinating metal ions for various applications.
- Understanding the structure-activity relationship of zinc(II) complexes is vital for designing effective catalysts.
- The hydrolysis of phosphate esters is a fundamental reaction with implications in biological systems and materials science.
Purpose of the Study:
- To compare the structural and functional properties of zinc(II) complexes formed with two distinct nitrogen-rich polydentate ligands: HTPDP and HTPPNOL.
- To investigate the catalytic activity of these zinc complexes in the hydrolysis of bis(2,4-dinitrophenyl)phosphate (BDNPP).
- To elucidate the reaction mechanisms and coordination modes involved in the catalytic process.
Main Methods:
- Synthesis and characterization of zinc(II) complexes with HTPDP and HTPPNOL ligands.
- Kinetic studies using bis(2,4-dinitrophenyl)phosphate (BDNPP) as a substrate at pH 8.5.
- 31P NMR spectroscopy to confirm hydrolysis products and reaction intermediates.
- X-ray crystallography to determine the structure of zinc complexes and their interaction with substrates.
Main Results:
- HTPDP formed a dinuclear zinc complex ([Zn2(TPDP)(OAc)](ClO4)2, 1), while HTPPNOL yielded mononuclear, dinuclear, and tetranuclear complexes.
- Compound 1 exhibited higher catalytic activity (kcat = 31.4 × 10-3 min-1) in BDNPP hydrolysis compared to the tetranuclear HTPPNOL complex (compound 3, kcat = 7.7 × 10-3 min-1).
- Compound 1 effectively hydrolyzed both ester bonds of BDNPP, yielding DNPP and inorganic phosphate. Compound 3 showed no substrate activity, and its crystal structure revealed an unusual tridentate coordination of the DNPP phosphate moiety.
Conclusions:
- The denticity and structural arrangement of the ligand significantly influence the nuclearity and catalytic activity of zinc(II) complexes.
- The dinuclear zinc complex 1 is a more efficient catalyst for BDNPP hydrolysis than the tetranuclear complex 3.
- The study highlights the importance of complex structure in dictating reactivity and substrate interaction in zinc-catalyzed phosphate ester hydrolysis.
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