Loading
PDBj
MenuPDBj@FacebookPDBj@TwitterPDBj@YouTubewwPDB FoundationwwPDB
RCSB PDBPDBeBMRBAdv. SearchSearch help
Search by PDB author
2HX3
DownloadVisualize
BU of 2hx3 by Molmil
Rat nNOS heme domain complexed with (4S)-N-{4-Amino-5-[(2-aminoethyl)-hydroxyamino]-pentyl}-N'-nitroguanidine
Descriptor: (4S)-N-{4-AMINO-5-[(2-AMINOETHYL)(HYDROXYAMINO]-PENTYL}-N'-NITROGUANIDINE, 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, ...
Authors:Igarashi, J, Li, H, Poulos, T.L.
Deposit date:2006-08-02
Release date:2007-04-24
Last modified:2024-02-14
Method:X-RAY DIFFRACTION (2 Å)
Cite:Structure-Based Design and Synthesis of N(omega)-Nitro-l-Arginine-Containing Peptidomimetics as Selective Inhibitors of Neuronal Nitric Oxide Synthase. Displacement of the Heme Structural Water.
J.Med.Chem., 50, 2007
3JT4
DownloadVisualize
BU of 3jt4 by Molmil
Structure of neuronal nitric oxide synthase heme domain complexed with N~5~-[(3-(ethylsulfanyl)propanimidoyl]-L-ornithine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, Nitric oxide synthase, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2009-09-11
Release date:2010-01-12
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.8 Å)
Cite:Heme-coordinating inhibitors of neuronal nitric oxide synthase. Iron-thioether coordination is stabilized by hydrophobic contacts without increased inhibitor potency.
J.Am.Chem.Soc., 132, 2010
3JT7
DownloadVisualize
BU of 3jt7 by Molmil
Structure of neuronal nitric oxide synthase heme domain complexed with N~5~-[2-(propylsulfanyl)ethanimidoyl]-L-ornithine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, Nitric oxide synthase, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2009-09-11
Release date:2010-01-12
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.1 Å)
Cite:Heme-coordinating inhibitors of neuronal nitric oxide synthase. Iron-thioether coordination is stabilized by hydrophobic contacts without increased inhibitor potency.
J.Am.Chem.Soc., 132, 2010
3JT5
DownloadVisualize
BU of 3jt5 by Molmil
Structure of neuronal nitric oxide synthase heme domain complexed with N~5~-[2-(ethylsulfanyl)ethanimidoyl]-L-ornithine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, Nitric oxide synthase, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2009-09-11
Release date:2010-01-12
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.1 Å)
Cite:Heme-coordinating inhibitors of neuronal nitric oxide synthase. Iron-thioether coordination is stabilized by hydrophobic contacts without increased inhibitor potency.
J.Am.Chem.Soc., 132, 2010
3JT9
DownloadVisualize
BU of 3jt9 by Molmil
Structure of neuronal nitric oxide synthase heme domain in the ferrous state complexed with N~5~-[2-(ethylsulfanyl)ethanimidoyl]-L-ornithine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, Nitric oxide synthase, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2009-09-11
Release date:2010-01-12
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.1 Å)
Cite:Heme-coordinating inhibitors of neuronal nitric oxide synthase. Iron-thioether coordination is stabilized by hydrophobic contacts without increased inhibitor potency.
J.Am.Chem.Soc., 132, 2010
3JT6
DownloadVisualize
BU of 3jt6 by Molmil
Structure of neuronal nitric oxide synthase heme domain complexed with N~5~-[4-(methylsulfanyl)butanimidoyl]-L-ornithine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, Nitric oxide synthase, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2009-09-11
Release date:2010-01-12
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.2 Å)
Cite:Heme-coordinating inhibitors of neuronal nitric oxide synthase. Iron-thioether coordination is stabilized by hydrophobic contacts without increased inhibitor potency.
J.Am.Chem.Soc., 132, 2010
3JT3
DownloadVisualize
BU of 3jt3 by Molmil
Structure of neuronal nitric oxide synthase heme domain complexed with N~5~-[2-(methylsulfanyl)ethanimidoyl]-L-ornithine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, Nitric oxide synthase, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2009-09-11
Release date:2010-01-12
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.15 Å)
Cite:Heme-coordinating inhibitors of neuronal nitric oxide synthase. Iron-thioether coordination is stabilized by hydrophobic contacts without increased inhibitor potency.
J.Am.Chem.Soc., 132, 2010
3N2R
DownloadVisualize
BU of 3n2r by Molmil
Structure of neuronal nitric oxide synthase heme domain in complex with 6-(((3R,4R/3S,4S)-4-(3-Phenoxyphenoxy)pyrrolidin-3-yl)methyl)pyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(3-phenoxyphenoxy)pyrrolidin-3-yl]methyl}pyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Poulos, T.L.
Deposit date:2010-05-18
Release date:2010-08-18
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.9 Å)
Cite:Structure-based design, synthesis, and biological evaluation of lipophilic-tailed monocationic inhibitors of neuronal nitric oxide synthase.
Bioorg.Med.Chem., 18, 2010
3NLM
DownloadVisualize
BU of 3nlm by Molmil
Structure of neuronal nitric oxide synthase heme domain in complex with 6-{{(3'R,4'R)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.85 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLQ
DownloadVisualize
BU of 3nlq by Molmil
Structure of neuronal nitric oxide synthase D597N/M336V mutant heme domain in complex with 6-{{(3'R,4'R)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 1,2-ETHANEDIOL, 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.15 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLV
DownloadVisualize
BU of 3nlv by Molmil
Structure of rat neuronal nitric oxide synthase heme domain in complex with 6-(((3S,4S)-4-(2-(2,2-Difluoro-2-(3-fluorophenyl)ethylamino)ethoxy)pyrrolidin-3-yl)methyl)-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3S,4S)-4-(2-{[2,2-difluoro-2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.1 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NLN
DownloadVisualize
BU of 3nln by Molmil
Structure of neuronal nitric oxide synthase R349A mutant heme domain in complex with 6-{{(3'R,4'S)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3S,4R)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLZ
DownloadVisualize
BU of 3nlz by Molmil
Structure of rat neuronal nitric oxide synthase heme domain in complex with 6-(((3R,4R)-4-(2-(2,2-Difluoro-2-phenylethylamino)ethoxy)pyrrolidin-3-yl)methyl)-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-{2-[(2,2-difluoro-2-phenylethyl)amino]ethoxy}pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.92 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NLK
DownloadVisualize
BU of 3nlk by Molmil
Structure of neuronal nitric oxide synthase R349A mutant heme domain in complex with 6-{{(3'S,4'S)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3S,4S)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.02 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLY
DownloadVisualize
BU of 3nly by Molmil
Structure of rat neuronal nitric oxide synthase heme domain in complex with 6-(((3R,4R)-4-(2- (2,2-Difluoro-2-(4-fluorophenyl)ethylamino)ethoxy)pyrrolidin-3-yl)methyl)-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2,2-difluoro-2-(4-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.99 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NLI
DownloadVisualize
BU of 3nli by Molmil
Structure of endothelial nitric oxide synthase N368D mutant heme domain complexed with 6-{{(3'R,4'R)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Delker, S.L, Li, H, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2024-02-21
Method:X-RAY DIFFRACTION (1.98 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLX
DownloadVisualize
BU of 3nlx by Molmil
Structure of rat neuronal nitric oxide synthase heme domain in complex with 6-(((3R,4R)-4-(2- (2,2-Difluoro-2-(3-fluorophenyl)ethylamino)ethoxy)pyrrolidin-3-yl)methyl)-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2,2-difluoro-2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.87 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NM0
DownloadVisualize
BU of 3nm0 by Molmil
Structure of rat neuronal nitric oxide synthase heme domain in complex with 6-(((3R,4R)-4-(2-(2,2-Difluoro-2-phenylethylamino)ethoxy) pyrrolidin-3-yl)methyl)-4-methyl-3,4,5,6-tetrahydropyridin-2-amine
Descriptor: (4S,6S)-6-{[(3R,4R)-4-{2-[(2,2-difluoro-2-phenylethyl)amino]ethoxy}pyrrolidin-3-yl]methyl}-4-methyl-3,4,5,6-tetrahydropyridin-2-amine, 5,6,7,8-TETRAHYDROBIOPTERIN, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (1.81 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NLT
DownloadVisualize
BU of 3nlt by Molmil
Structure of endothelial nitric oxide synthase heme domain complexed with N1-{(3'S,4'S)-4'-[(6"-amino-4"-methylpyridin-2"-yl)methyl]pyrrolidin-3'-yl}- N2-(3'-fluorophenethyl)ethane-1,2-diamine tetrahydrochloride
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-({(3S,4S)-4-[2-({2,2-difluoro-2-[(2R)-piperidin-2-yl]ethyl}amino)ethoxy]pyrrolidin-3-yl}methyl)-4-methylpyridin-2-amine, CACODYLIC ACID, ...
Authors:Xue, F, Li, H, Fang, J, Delker, S.L, Poulos, T.L, Silverman, R.B.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2024-02-21
Method:X-RAY DIFFRACTION (2.74 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NLR
DownloadVisualize
BU of 3nlr by Molmil
Structure of neuronal nitric oxide synthase D597N/M336V mutant heme domain in complex with 6-{{(3'R,4'S)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3S,4R)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.1 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLH
DownloadVisualize
BU of 3nlh by Molmil
Structure of endothelial nitric oxide synthase heme domain N368D mutant complexed with 6-{{(3'S,4'S)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3S,4S)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Delker, S.L, Li, H, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2024-02-21
Method:X-RAY DIFFRACTION (2.1 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLU
DownloadVisualize
BU of 3nlu by Molmil
Structure of endothelial nitric oxide synthase heme domain complexed with N1-{(3'R,4'R)-4'-[(6"-amino-4"-methylpyridin-2"-yl)methyl]pyrrolidin-3'-yl}-N2-(3'-fluorophenethyl)ethane-1,2-diamine tetrahydrochloride
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2,2-difluoro-2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Xue, F, Li, H, Fang, J, Delker, S.L, Poulos, T.L, Silverman, R.B.
Deposit date:2010-06-21
Release date:2011-01-19
Last modified:2024-02-21
Method:X-RAY DIFFRACTION (2.65 Å)
Cite:Potent, highly selective, and orally bioavailable gem-difluorinated monocationic inhibitors of neuronal nitric oxide synthase.
J.Am.Chem.Soc., 132, 2010
3NLP
DownloadVisualize
BU of 3nlp by Molmil
Structure of neuronal nitric oxide synthase D597N/M336V mutant heme domain in complex with 6-{{(3'S,4'S)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3S,4S)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.02 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLO
DownloadVisualize
BU of 3nlo by Molmil
Structure of neuronal nitric oxide synthase R349A mutant heme domain in complex with 6-{{(3'S,4'R)-3'-[2"-(3'''-fluorophenethylamino)ethoxy]pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 1,2-ETHANEDIOL, 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4S)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ...
Authors:Li, H, Delker, S.L, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2023-09-06
Method:X-RAY DIFFRACTION (2.3 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010
3NLJ
DownloadVisualize
BU of 3nlj by Molmil
Structure of neuronal nitric oxide synthase D597N/M336V/Y706A triple mutant heme domain complexed with 6-{{(3'R,4'R)-3'-[2"-(3'''-fluorophenethylamino)ethoxy] pyrrolidin-4'-yl}methyl}-4-methylpyridin-2-amine
Descriptor: 5,6,7,8-TETRAHYDROBIOPTERIN, 6-{[(3R,4R)-4-(2-{[2-(3-fluorophenyl)ethyl]amino}ethoxy)pyrrolidin-3-yl]methyl}-4-methylpyridin-2-amine, ACETATE ION, ...
Authors:Delker, S.L, Li, H, Poulos, T.L.
Deposit date:2010-06-21
Release date:2010-11-03
Last modified:2024-02-21
Method:X-RAY DIFFRACTION (2.2 Å)
Cite:Exploration of the Active Site of Neuronal Nitric Oxide Synthase by the Design and Synthesis of Pyrrolidinomethyl 2-Aminopyridine Derivatives.
J.Med.Chem., 53, 2010

220113

數據於2024-05-22公開中

PDB statisticsPDBj update infoContact PDBjnumon