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S617D
the phosphomimetic substitution doubles the maximum calmodulin-dependent enzyme activity and decreases the EC50(Ca2+) values for calmodulin binding and enzyme activation compared to the wild type enzyme
S617D/S1179D
the mutation doubles maximal synthase activity, partially disinhibits cytochrome c reductase activity, and lowers the EC50(Ca2+) values for calmodulin binding and enzyme activation
S617D/S635D
the maximum calmodulin-dependent synthase activity of S617/635D eNOS is about 2fold higher than the wild type activity
S635D
the substitution has little or no effect on enzyme activity
C563R
interdomain electron transfer rate is similar to that of the wildtype
D597N/M336V
mutant of nNOS, the Ki values for the nNOS double mutant increase for all inhibitors but the mutant still binds these inhibitors better than eNOS
E298D
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comparable to wild-type in heme and flavin content, in affinity to calmodulin and dimerization
G2A
the mutant is defective in activity and cellular localization
R536E
mutant constructed to disrupt the bridging calmodulin/nitric oxide synthase interaction. The FMN-heme interdomain electron transfer rate is decreased by 96%
S562K
inducible nitric oxide synthase mutant in an oxygenase/FMN construct. The interdomain electron transfer rate constant of the mutant is decreased by one third, and its flavin fluorescence intensity per micromole per liter is diminished by approximately 24% suggesting that a positive charge at position 562 destabilizes the hydrogen-bond-mediated nitric oxide synthase/calmodulin alignment, resulting in slower FMN-heme interdomain electron transfer
C415A
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contains no heme, no bound tetrahydrobiopterin, unable to oxidize NADPH and to synthezise nitric oxide, unaltered ability to reduce cytochrome c
C415H
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contains nearly no heme, no bound tetrahydrobiopterin, unable to oxidize NADPH and to synthezise nitric oxide, unaltered ability to reduce cytochrome c
N695Q
site-directed mutagenesis, mutating Asn695 to Gln695 yields an iNOS that exhibits greater enzyme activity compared to wild-type. NO produced by N695Q iNOS-transformed HEK293 cells is 1.32fold greater than that of N-glycosylated iNOS, the increased enzyme activity of N695Q iNOS in HEK293 cells was caused by loss of N-glycan
V346I
slower NO-binding and dissociation than wild-type
W457A
increase in Km-value of tetrahydrobiopterin and L-arginine, decrease in NO synthesis activity, slower building of enzyme heme-NO complex and slower reactivity of heme-dioxy intermediate
N695Q
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site-directed mutagenesis, mutating Asn695 to Gln695 yields an iNOS that exhibits greater enzyme activity compared to wild-type. NO produced by N695Q iNOS-transformed HEK293 cells is 1.32fold greater than that of N-glycosylated iNOS, the increased enzyme activity of N695Q iNOS in HEK293 cells was caused by loss of N-glycan
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D1393E
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normal composition, spectral properties and binding of cofactors, substrates and calmodulin, slower NADPH-dependent cytochrome c and ferricyanide reductase activity
D1393N
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normal composition, spectral properties and binding of cofactors, substrates and calmodulin, slower NADPH-dependent cytochrome c and ferricyanide reductase activity
D1393V
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normal composition, spectral properties and binding of cofactors, substrates and calmodulin, slower NADPH-dependent cytochrome c and ferricyanide reductase activity
DELTAG810
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deletion changes redox behaviour of mutant. In the early stage of flavin reduction, similar to the case of wild-type, the hydroquinone FADH2-FMN quickly converts to the disemiquinone and does not accumulate. Since more FADH2-FMN is generated and not consumed quickly enough, the decreased flavin absorption band of FADH2-FMN will blur the isosbestic point after 100 ms, most likely due to a slower two-electron reduction of FMN in the mutant
V567E
little stability, no enzymic activity
V567F
enzymic activity only with N-hydroxy-L-arginine
V567L
little production of NO, lower affinity for L-arginine and N-hydroxy-L-arginine than wild-type
V567R
little stability, no enzymic activity
W678A
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increase in Km-value of tetrahydrobiopterin, decrease in NO synthesis activity, slower building of enzyme heme-NO complex and slower reactivity of heme-dioxy intermediate
W678F
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increase in Km-value of tetrahydrobiopterin, decrease in NO synthesis activity, slower building of enzyme heme-NO complex and slower reactivity of heme-dioxy intermediate
I224V
little effect on binding of L-arginie, tetrahydrobiopterin or in electronic properties
I224V
mutation does not greatly alter binding of Arg, (6R)-tetrahydrobiopterin, or alter the electronic properties of the heme or various heme-ligand complexes. I224V displays three heme transitions involving four species as typically occurs in wild-type NOS, the beginning ferrous enzyme, a ferrous-dioxy (FeIIO2) intermediate, FeIIINO, and an ending ferric enzyme. The rate of each transition is increased relative to wild-type, with FeIIINO dissociation being 3.6 times faster
I224V
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mutation does not greatly alter binding of Arg, (6R)-tetrahydrobiopterin, or alter the electronic properties of the heme or various heme-ligand complexes. I224V displays three heme transitions involving four species as typically occurs in wild-type NOS, the beginning ferrous enzyme, a ferrous-dioxy (FeIIO2) intermediate, FeIIINO, and an ending ferric enzyme. The rate of each transition is increased relative to wild-type, with FeIIINO dissociation being 3.6 times faster
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S1179D
the phosphomimetic substitution at Ser-1179 doubles maximal synthase activity, partially disinhibits cytochrome c reductase activity, and lowers the EC50(Ca2+) values for calmodulin binding and enzyme activation about 35%
S1179D
mutation augments enzyme activity and increases its sensitivity to heat shock protein 90 (Hsp90). Mutation of Ser1179 to aspartic acid plays a dominant role in changing the sensitivity of the enzyme to NADPH.
additional information
deletion of the autoinhibitory domain doubles the maximum calmodulin-dependent enzyme activity and decreases the EC50(Ca2+) values for calmodulin binding and calmodulin-dependent enzyme activation
additional information
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deletion of the autoinhibitory domain doubles the maximum calmodulin-dependent enzyme activity and decreases the EC50(Ca2+) values for calmodulin binding and calmodulin-dependent enzyme activation
additional information
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enhancement of nitric oxide production by association of neuronal nitric oxide synthase with N-methyl-D-aspartate receptors via postsynaptic density 95 proteins in genetically engineered Chinese hamster ovary cells, method development and quantitative analysis, overview
additional information
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construction of a heterodimer with one subunit being His-tagged
additional information
monomers encoding NOS oxygenase domain lacking the N-terminal 114 residues, His-tagged, expression in Escherichia coli
additional information
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monomers encoding NOS oxygenase domain lacking the N-terminal 114 residues, His-tagged, expression in Escherichia coli
additional information
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naturally occuring neuronal mutant with a 105-amino acid deletion in the heme-binding domain as a result of in-frame mutation by specific alternative splicing, contains heme, but shows no L-arginine and NADPH-dependent citrulline-forming activity in presence of Ca2+-promoted calmodulin
additional information
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construction of eNOS and of iNOS knockout mice, phenotype, overview
additional information
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generation of mice chimeric for iNOS expression, wild-type animals receive bone marrow cells from CD45.1-expressing congenic wild-type mice, resulting in three different chimeric strains, phenotype with induced colitis, overview
additional information
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knock out mice deficient for the splice-isoform alpha of neuronal nitric oxide synthase display residual nitric oxide synthase activity and immunosignal
additional information
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mutant DELTA296nNOS, missing N-terminal leader sequence, no impact on enzyme structure or catalysis, mutant DELTA349nNOS, missing N-terminal leader sequence plus three core motifs, weaker dimer interaction, slowerferric heme production, 10fold poorer affinity towards L-arginine
additional information
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construction of a truncated mutant lacking the terminal half of the C-terminus, i.e. residues from Ile1413 to Ser1429. The mutation has almost no impact on NADP+ release, flavin reduction, flavin autoxidation, heme reduction, reductase activity, or NO synthesis activity, but does prevent an increase in FMN shielding that normally occurs in response to NADPH binding. Additional removal of the C-terminal alpha-helix, residues 1401 to 1412, significantly increases the NADP+ release rate, flavin autoxidation, and NADPH oxidase activity, and causes hyper-deshielding of the FMN cofactor associated with increased reductase activity and slightly diminished heme reduction and NO synthesis. Further removal of residues downstream from Gly1396, a full C-terminus truncation, amplifies the aforementioned effects and in addition altered NADP+ interaction with FAD, relieves the kinetic suppression on flavin reduction, and further diminishes heme reduction and NO synthesis
additional information
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knock out mice deficient for the splice-isoform alpha of neuronal nitric oxide synthase display residual nitric oxide synthase activity and immunosignal, phenotype, overview
additional information
the DELTAG810 mutant enzyme shows strongly reduced activity towards nitric oxide synthesis and NADPH oxidation compared to the wild type enzyme