Activating Compound | Comment | Organism | Structure |
---|---|---|---|
HDL | modulation of substrate selectivity and catalytic stimulation by HDL | Oryctolagus cuniculus |
Application | Comment | Organism |
---|---|---|
medicine | PON1 shows great promise as a biotherapeutic due to its role in atherosclerosis and because of its ability to hydrolyze a broad range of organophosphates, including pesticides and nerve agents such as sarin, soman, and VX | Oryctolagus cuniculus |
Protein Variants | Comment | Organism |
---|---|---|
additional information | modulating the active site hydrophobicity is a key element in facilitating the evolution of organophosphatase activity. Molecular dynamics simulations of wild-type and mutant PON1 enzymes, detailed overview | Oryctolagus cuniculus |
Y71A | site-directed mutagenesis, the mutant shows an increased active site volume compared to the wild-type | Oryctolagus cuniculus |
Y71F | site-directed mutagenesis, the mutant shows an increased active site volume compared to the wild-type | Oryctolagus cuniculus |
Y71G | site-directed mutagenesis, the mutant shows reduced lactonase and paraoxonase activities compared to the wild-type enzyme, the mutant shows an increased active site volume compared to the wild-type | Oryctolagus cuniculus |
Y71M | site-directed mutagenesis, the mutant shows reduced lactonase and paraoxonase activities compared to the wild-type enzyme, the mutant shows an increased active site volume compared to the wild-type | Oryctolagus cuniculus |
Y71W | site-directed mutagenesis, the mutant shows an increased active site volume compared to the wild-type | Oryctolagus cuniculus |
Y71X | site-saturation library screening. The impact of Y71 mutational substitutions on PON1's lactonase activity is minimal, whereas the kcat for the paraoxonase activity is negatively perturbed by up to 100fold, suggesting greater mutational robustness of the native activity. Additionally, while these substitutions modulate PON1's active site shape, volume, and loop flexibility, their largest effect is in altering the solvent accessibility of the active site by expanding the active site volume, allowing additional water molecules to enter. This effect is markedly more pronounced in the organophosphatase activity than the lactonase activity. Differential effect of mutating Y71 on the native and promiscuous activities of PON1, detailed overview | Oryctolagus cuniculus |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
2-hydroxyquinoline | enzyme-bound structure, overview | Oryctolagus cuniculus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Michaelis-Menten kinetics | Oryctolagus cuniculus |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Ca2+ | dependent on, catalytic Ca2+ ion | Oryctolagus cuniculus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
diethyl-paraoxon + H2O | Oryctolagus cuniculus | - |
diethyl phosphate + 4-nitrophenol | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Oryctolagus cuniculus | P27170 | - |
- |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
an aryl dialkyl phosphate + H2O = dialkyl phosphate + an aryl alcohol | reaction mechanism of lactonase activity and paraoxonase activity of the enzyme PON1, overview | Oryctolagus cuniculus |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
serum | - |
Oryctolagus cuniculus | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
diethyl-paraoxon + H2O | - |
Oryctolagus cuniculus | diethyl phosphate + 4-nitrophenol | - |
? | |
diethyl-paraoxon + H2O | both docking and molecular dynamics simulations suggest that the only way paraoxon can be accommodated in the PON1 active site is by pushing Y71 out of the active site, causing the active site loop to take on a partially open conformation | Oryctolagus cuniculus | diethyl phosphate + 4-nitrophenol | - |
? | |
additional information | th enzyme is also active with the chromogenic lactone thiobutyl-gamma-butyric lactone (TBBL), cf. EC 3.1.1.81. It has both lactonase activity and paraoxonase activity. Empirical valence bond simulations of PON1-catalyzed hydrolyses of paraoxon and TBBL, overview | Oryctolagus cuniculus | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
More | enzyme PON1 is a six-bladed beta-propeller with a flexible loop (residues 70-81) covering the active site | Oryctolagus cuniculus |
Synonyms | Comment | Organism |
---|---|---|
More | cf. EC 3.1.1.81 | Oryctolagus cuniculus |
paraoxonase 1 | - |
Oryctolagus cuniculus |
PON1 | - |
Oryctolagus cuniculus |
serum paraoxonase 1 | - |
Oryctolagus cuniculus |
General Information | Comment | Organism |
---|---|---|
evolution | serum paraoxonase 1 (PON1) is a native lactonase capable of promiscuously hydrolyzing a broad range of substrates, including organophosphates, esters, and carbonates. Comparison of PON1 to other organophosphatases demonstrates that either a similar gating loop or a highly buried solvent excluding active site is a common feature of these enzymes | Oryctolagus cuniculus |
malfunction | the impact of Y71 mutational substitutions on PON1's lactonase activity is minimal, whereas the kcat for the paraoxonase activity is negatively perturbed by up to 100fold, suggesting greater mutational robustness of the native activity. Additionally, while these substitutions modulate PON1's active site shape, volume, and loop flexibility, their largest effect is in altering the solvent accessibility of the active site by expanding the active site volume, allowing additional water molecules to enter. This effect is markedly more pronounced in the organophosphatase activity than the lactonase activity | Oryctolagus cuniculus |
additional information | enzyme PON1 is a six-bladed beta-propeller with a flexible loop (residues 70-81) covering the active site. This loop contains a functionally critical Tyr at position 71, mutational analysis of the role of Y71 in PON1's lactonase and organophosphatase activities. The side chain of Y71 is highly mobile and has been shown to adopt various conformational substrates that have been suggested to differentially affect PON1's native and promiscuous functions. Residue Y71 does not play an active role in PON1's lactonase activity in general, and specifically not on the HDL-induced simulation. Molecular dynamics simulations of PON1, e.g. using crystal structure of RePON1 in complex with the inhibitor 2-hydroxyquinoline (2HQ) and obtained at pH 6.5 (PDB ID 3SRG). In the wild-type enzyme Y71 forms a hydrogen-bonding interaction with the side chain of D183, which is itself part of a hydrogen-bonding network that leads from N168 on the catalytic Ca2+ ion to the outer periphery of the protein. D183 is central to this hydrogen-bonding network, as in addition to the hydrogen bond it forms with the side chain of Y71, it also forms hydrogen-bonding interactions with the side chains of S166, N168, and H184, the backbone carbonyl group of S166, and an active site water molecule. Therefore, D183 acts as an anchor, keeping this hydrogen-bonding network together. Active site hydrophobicity and the role of the active site loop in determining substrate selectivity, active site structure, structure-function relationship, overview | Oryctolagus cuniculus |
physiological function | serum paraoxonase 1 (PON1) is a native lactonase capable of promiscuously hydrolyzing a broad range of substrates, including organophosphates, esters, and carbonates. PON1 is a calcium-dependent hydrolytic enzyme that is found in all mammalian species. In vivo, this enzyme forms complexes with the membrane-like surface of high-density lipoprotein (HDL) and contributes to HDL's antioxidant properties. Modulation of substrate selectivity and catalytic stimulation by HDL | Oryctolagus cuniculus |