1NSI: Protein

Human inducible nitric oxide synthase, ZN-bound, L-arg complex. Determined by X-ray diffraction at 2.55 Å resolution. Released 7 Jan 2000.

Method: X-ray diffraction
Resolution: 2.55 Å
Organism: Homo sapiens
Chains: 4
Atoms: 14,330
Mol. weight: 204.32 kDa
Ligands: ARG, H4B, HEM, ZN
Released: 7 Jan 2000

Explore 1NSI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1NSI contains 105 α-helices and 114 β-strands across 4 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 29 helices, 31 β-strands

Element	Residues	Length	Sheet
β-strand	85-88	4	1
β-strand	89	1	2
β-strand	95-98	4	1
α-helix	100-102	3
β-strand	105	1	3
β-strand	115	1	4
α-helix	123-125	3
β-strand	126	1	5
α-helix	133-135	3
α-helix	136-152	17
α-helix	159-176	18
α-helix	183-195	13
α-helix	203-205	3
β-strand	210-213	4	6
α-helix	220-235	16
α-helix	236-238	3
β-strand	243-246	4	6
α-helix	247-250	4
β-strand	258-259	2	7
β-strand	263	1	6
β-strand	267	1	8
β-strand	269-271	3	9
β-strand	277-279	3	9
α-helix	281-283	3
α-helix	284-292	9
α-helix	295-297	3
α-helix	303	1
β-strand	304	1	8
α-helix	305-306	2
β-strand	307-310	4	7
α-helix	315-316	2
β-strand	317-319	3	7
α-helix	320-322	3
α-helix	323-325	3
β-strand	328-330	3	10
α-helix	337-342	6
β-strand	345-347	3	10
β-strand	351-352	2	6
β-strand	356-359	4	11
β-strand	362-364	3	11
β-strand	369-370	2	6
β-strand	373-374	2	12
α-helix	375-376	2
α-helix	377-382	6
α-helix	383-384	2
α-helix	392-398	7
α-helix	406-408	3
α-helix	410-428	19
β-strand	433-434	2	12
α-helix	436-453	18
β-strand	458	1	13
α-helix	461-464	4
α-helix	470-472	3
β-strand	478	1	2
β-strand	481	1	13
β-strand	482	1	14
β-strand	484	1	3
β-strand	488-490	3	11
β-strand	491	1	5
α-helix	495-498	4

Chain B: 26 helices, 27 β-strands

Element	Residues	Length	Sheet
β-strand	85-88	4	15
β-strand	89	1	16
β-strand	95-98	4	15
α-helix	100-103	4
β-strand	115	1	14
α-helix	123-125	3
β-strand	126	1	17
α-helix	133-135	3
α-helix	136-153	18
α-helix	159-176	18
α-helix	183-195	13
α-helix	203-205	3
β-strand	210-213	4	18
α-helix	220-235	16
α-helix	236-238	3
β-strand	243-246	4	18
α-helix	247-250	4
β-strand	258-259	2	19
β-strand	263	1	18
β-strand	267	1	20
β-strand	269-271	3	21
β-strand	277-279	3	21
α-helix	281-283	3
α-helix	284-292	9
β-strand	304	1	20
α-helix	305-306	2
β-strand	307-310	4	19
β-strand	317-319	3	19
α-helix	323-325	3
β-strand	328-330	3	22
α-helix	337-342	6
β-strand	345-347	3	22
β-strand	351-352	2	18
β-strand	356-359	4	23
β-strand	362-364	3	23
β-strand	369-370	2	18
β-strand	374	1	24
α-helix	375-376	2
α-helix	377-382	6
α-helix	383-384	2
α-helix	392-399	8
α-helix	406-408	3
α-helix	410-428	19
β-strand	434	1	24
α-helix	436-453	18
α-helix	461-464	4
α-helix	470-472	3
α-helix	474-477	4
β-strand	478	1	16
β-strand	482	1	4
β-strand	488-490	3	23
β-strand	491	1	17
α-helix	495-497	3

Chain C: 27 helices, 29 β-strands

Element	Residues	Length	Sheet
β-strand	85-88	4	25
β-strand	89	1	26
β-strand	95-98	4	25
α-helix	100-103	4
β-strand	111	1	27
β-strand	114	1	27
β-strand	115	1	28
α-helix	123-125	3
β-strand	126	1	29
α-helix	136-151	16
α-helix	159-176	18
α-helix	180-182	3
α-helix	183-195	13
α-helix	203-205	3
β-strand	210-213	4	30
α-helix	220-235	16
α-helix	236-238	3
β-strand	243-246	4	30
β-strand	258-259	2	31
β-strand	263	1	30
β-strand	267	1	32
β-strand	269-271	3	33
β-strand	277-279	3	33
α-helix	281-283	3
α-helix	284-292	9
α-helix	303	1
β-strand	304	1	32
α-helix	305-306	2
β-strand	307-310	4	31
α-helix	315-316	2
β-strand	317-319	3	31
α-helix	320-322	3
α-helix	323-325	3
β-strand	328-330	3	34
α-helix	337-342	6
β-strand	345-347	3	34
β-strand	351-352	2	30
β-strand	356-359	4	35
β-strand	362-364	3	35
β-strand	369-370	2	30
β-strand	374	1	36
α-helix	375-376	2
α-helix	377-382	6
α-helix	383-384	2
α-helix	392-398	7
α-helix	406-408	3
α-helix	410-428	19
β-strand	434	1	36
α-helix	436-453	18
α-helix	461-464	4
α-helix	470-472	3
β-strand	478	1	26
β-strand	482	1	37
β-strand	488-490	3	35
β-strand	491	1	29
α-helix	495-497	3

Chain D: 23 helices, 27 β-strands

Element	Residues	Length	Sheet
β-strand	85-88	4	38
β-strand	89	1	39
β-strand	95-98	4	38
α-helix	100-103	4
β-strand	115	1	37
α-helix	123-125	3
β-strand	126	1	40
α-helix	133-135	3
α-helix	136-152	17
α-helix	159-175	17
α-helix	183-195	13
α-helix	203-205	3
β-strand	210-213	4	41
α-helix	220-235	16
α-helix	236-238	3
β-strand	243-246	4	41
β-strand	258-259	2	42
β-strand	263	1	41
β-strand	267	1	43
β-strand	269-271	3	44
β-strand	277-279	3	44
α-helix	281-283	3
α-helix	284-292	9
β-strand	304	1	43
β-strand	307-310	4	42
β-strand	317-319	3	42
β-strand	328-330	3	45
α-helix	337-342	6
β-strand	345-347	3	45
β-strand	351-352	2	41
β-strand	356-358	3	46
β-strand	364	1	46
β-strand	369-370	2	41
β-strand	373-374	2	47
α-helix	375-376	2
α-helix	377-382	6
α-helix	383-384	2
α-helix	392-398	7
α-helix	406-408	3
α-helix	410-428	19
β-strand	433-434	2	47
α-helix	436-453	18
α-helix	461-464	4
α-helix	470-472	3
α-helix	474-477	4
β-strand	478	1	39
β-strand	482	1	28
β-strand	488-490	3	46
β-strand	491	1	40
α-helix	495-497	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Protein (nitric oxide synthase)	A, B, C, D	protein	431	Homo sapiens	P35228 (AlphaFold model)

Sequence of entity 1 (A, B, C, D), FASTA

>1NSI_1 PROTEIN (NITRIC OXIDE SYNTHASE) (chains A, B, C, D)
LDATPLSSPRHVRIKNWGSGMTFQDTLHHKAKGILTCRSKSCLGSIMTPKSLTRGPRDKP
TPPDELLPQAIEFVNQYYGSFKEAKIEEHLARVEAVTKEIETTGTYQLTGDELIFATKQA
WRNAPRCIGRIQWSNLQVFDARSCSTAREMFEHICRHVRYSTNNGNIRSAITVFPQRSDG
KHDFRVWNAQLIRYAGYQMPDGSIRGDPANVEFTQLCIDLGWKPKYGRFDVVPLVLQANG
RDPELFEIPPDLVLEVAMEHPKYEWFRELELKWYALPAVANMLLEVGGLEFPGCPFNGWY
MGTEIGVRDFCDVQRYNILEEVGRRMGLETHKLASLWKDQAVVEINIAVLHSFQKQNVTI
MDHHSAAESFMKYMQNEYRSRGGCPADWIWLVPPMSGSITPVFHQEMLNYVLSPFYYYQV
EAWKTHVWQDE

Ligands and cofactors

ID	Name	Formula	Copies
ARG	Arginine	C6 H15 N4 O2	4
H4B	5,6,7,8-tetrahydrobiopterin	C9 H15 N5 O3	4
HEM	Protoporphyrin IX containing FE	C34 H32 Fe N4 O4	4
ZN	Zinc ion	Zn	2

Water and common crystallization additives (GOL, SO4) are not listed.

Primary citation

Crystal structures of zinc-free and -bound heme domain of human inducible nitric-oxide synthase. Implications for dimer stability and comparison with endothelial nitric-oxide synthase. Li, H., Raman, C.S., Glaser, C.B. et al. J Biol Chem (1999) 274:21276-21284. DOI 10.1074/jbc.274.30.21276 · PubMed

Other PDB entries of the same protein (UniProt P35228 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6JWM 1.23 Å, Crystal structure of the SPRY domain of SPSB2 in complex with cR7, a potent cyclic…
6KEY 1.24 Å, Structural basis for the regulation of inducible nitric oxide synthase (iNOS) by the…
5XN3 1.34 Å, Crystal structure of SPSB2 in complex with a rational designed RGD containing cyclic…
6JWN 1.61 Å, Crystal structure of the SPRY domain of SPSB2 in complex with cR9, a cyclic peptide…
3E7G 2.2 Å, Structure of human INOSOX with inhibitor AR-C95791
4NOS 2.25 Å, Human inducible nitric oxide synthase with inhibitor
3HR4 2.5 Å, Human iNOS Reductase and Calmodulin Complex
3EJ8 2.55 Å, Structure of double mutant of human iNOS oxygenase domain with bound immidazole
2NSI 3.0 Å, Human inducible nitric oxide synthase, ZN-free, seitu complex
4CX7 3.16 Å, Structure of human iNOS heme domain in complex with (R)-6-(3-AMINO-2-(5-(2-(6-AMINO-4-…
2LL6 Solution NMR structure of CaM bound to iNOS CaM binding domain peptide
5TP6 Solution structure of the CaM34 with the iNOS CaM binding domain peptide

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