Reviewed, UniProtKB/Swiss-Prot Q56224 (NQO9_THET8)

Names and origin

Protein names

Recommended name:
    NADH-quinone oxidoreductase subunit 9
    EC=1.6.99.5
Alternative name(s):
    NADH dehydrogenase I subunit 9
    NDH-1 subunit 9

Gene names

Name:	nqo9
Ordered Locus Names:	TTHA0092

Organism

Thermus thermophilus (strain HB8 / ATCC 27634 / DSM 579) [Complete proteome] [HAMAP]

Taxonomic identifier

300852 [NCBI]

Taxonomic lineage

Bacteria › Deinococcus-Thermus › Deinococci › Thermales › Thermaceae › Thermus

Protein attributes

Sequence length	182 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	NDH-1 shuttles electrons from NADH, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. The immediate electron acceptor for the enzyme in this species is menaquinone. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient required for the synthesis of ATP. The role of the nqo9 subunit appears to provide a 'connecting chain' of two clusters between cluster N5 and the terminal cluster N2, and to stabilize the structure of the complex by interacting with other subunits. HAMAP MF_01351
Catalytic activity	NADH + quinone = NAD+ + quinol. HAMAP MF_01351
Cofactor	Binds 2 4Fe-4S clusters per subunit. The 4Fe-4S clusters are referred to as N6a and N6b. HAMAP MF_01351
Subunit structure	NDH-1 is composed of 15 different subunits, nqo1 to nqo15. The complex has a L-shaped structure, with the hydrophobic arm (subunits nqo7, nqo8 and nqo10 to nqo14) embedded in the membrane and the hydrophilic peripheral arm (subunits nqo1 to nqo6, nqo9 and nqo15) protruding into the bacterial cytoplasm. The hydrophilic domain contains all the redox centers. Ref.3 Ref.4
Subcellular location	Cell membrane; Peripheral membrane protein; Cytoplasmic side. HAMAP MF_01351
Sequence similarities	Belongs to the complex I 23 kDa subunit family. Contains 2 4Fe-4S ferredoxin-type domains.

Ontologies

Keywords
Cellular component	Cell membrane Membrane
Domain	Repeat
Ligand	4Fe-4S Iron Iron-sulfur Metal-binding NAD
Molecular function	Oxidoreductase
PTM	Quinone
Technical term	3D-structure Complete proteome
Gene Ontology (GO)
Biological process	oxidation reduction Inferred from electronic annotation. Source: HAMAP photosynthesis, light reaction Inferred from electronic annotation. Source: HAMAP
Cellular component	plasma membrane Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	4 iron, 4 sulfur cluster binding Inferred from electronic annotation. Source: UniProtKB-KW NADH dehydrogenase (quinone) activity Inferred from electronic annotation. Source: EC electron carrier activity Inferred from electronic annotation. Source: InterPro iron ion binding Inferred from electronic annotation. Source: HAMAP quinone binding Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 182

182

NADH-quinone oxidoreductase subunit 9 HAMAP MF_01351

PRO_0000118721

Regions

Domain

43 – 73

31

4Fe-4S ferredoxin-type 1

Domain

89 – 118

30

4Fe-4S ferredoxin-type 2

Sites

Metal binding

53

1

Iron-sulfur 1 (4Fe-4S) HAMAP MF_01351

Metal binding

56

1

Iron-sulfur 1 (4Fe-4S) HAMAP MF_01351

Metal binding

59

1

Iron-sulfur 1 (4Fe-4S) HAMAP MF_01351

Metal binding

63

1

Iron-sulfur 2 (4Fe-4S) HAMAP MF_01351

Metal binding

98

1

Iron-sulfur 2 (4Fe-4S) HAMAP MF_01351

Metal binding

101

1

Iron-sulfur 2 (4Fe-4S) HAMAP MF_01351

Metal binding

104

1

Iron-sulfur 2 (4Fe-4S) HAMAP MF_01351

Metal binding

108

1

Iron-sulfur 1 (4Fe-4S) HAMAP MF_01351

Secondary structure

1

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182

Helix Strand Turn

Details...

Beta strand

40 – 43

4

Helix

58 – 62

5

Beta strand

68 – 74

7

Beta strand

77 – 79

3

Beta strand

81 – 94

14

Turn

95 – 97

3

Helix

103 – 107

5

Beta strand

109 – 111

3

Beta strand

113 – 115

3

Helix

126 – 128

3

Beta strand

129 – 131

3

Turn

134 – 136

3

Helix

144 – 153

10

Beta strand

160 – 162

3

Turn

169 – 172

4

Sequences

	Sequence		Length	Mass (Da)
	Q56224-1 [UniParc]. Last modified November 1, 1997. Version 1. Checksum: 054A9F7942C64C66	FASTA	182	20,080
	10 20 30 40 50 60 MTLKALAQSL GITLKYLFSK PVTVPYPDAP VALKPRFHGR HVLTRHPNGL EKCIGCSLCA 70 80 90 100 110 120 AACPAYAIYV EPAENDPENP VSAGERYAKV YEINMLRCIF CGLCEEACPT GAIVLGYDFE 130 140 150 160 170 180 MADYEYSDLV YGKEDMLVDV VGTKPQRREA KRTGKPVKVG YVVPYVRPEL EGFKAPTEGG KR

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The proton-translocating NADH-quinone oxidoreductase (NDH-1) of thermophilic bacterium Thermus thermophilus HB-8. Complete DNA sequence of the gene cluster and thermostable properties of the expressed NQO2 subunit." Yano T., Chu S.S., Sled' V.D., Ohnishi T., Yagi T. J. Biol. Chem. 272:4201-4211(1997) [PubMed: 9020134] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Complete genome sequence of Thermus thermophilus HB8." Masui R., Kurokawa K., Nakagawa N., Tokunaga F., Koyama Y., Shibata T., Oshima T., Yokoyama S., Yasunaga T., Kuramitsu S. Submitted (NOV-2004) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
[3]	"Identification of a novel subunit of respiratory complex I from Thermus thermophilus." Hinchliffe P., Carroll J., Sazanov L.A. Biochemistry 45:4413-4420(2006) [PubMed: 16584177] [Abstract] Cited for: IDENTIFICATION BY MASS SPECTROMETRY, SUBUNIT.
[4]	"Structure of the hydrophilic domain of respiratory complex I from Thermus thermophilus." Sazanov L.A., Hinchliffe P. Science 311:1430-1436(2006) [PubMed: 16469879] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (3.3 ANGSTROMS), SUBUNIT, ELECTRON TRANSFER MECHANISM.

Cross-references

Sequence databases

EMBLGenBankDDBJ

U52917 Genomic DNA. Translation: AAA97946.1.
AP008226 Genomic DNA. Translation: BAD69915.1.

PIR

T11906.

RefSeq

YP_143358.1.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2FUG	X-ray	3.30	9/G/P/Y	1-182	[»]

ModBase

Search...

Protein family/group databases

TCDB

3.D.1.3.1. proton-translocating NADH dehydrogenase (NDH) family.

Genome annotation databases

GeneID

3167944.

GenomeReviews

Gene locus TTHA0092 in contig AP008226_GR.

KEGG

ttj:TTHA0092.

Organism-specific databases

CMR

Search...

Phylogenomic databases

HOGENOM

Q56224.

OMA

Q56224. FARCIFC.

Enzyme and pathway databases

BioCyc

TTHE300852:TTHA0092-MON.

Family and domain databases

HAMAP

MF_01351.
[Tree]

InterPro

IPR017896. 4Fe4S_Fe-S-bd.
IPR001450. 4Fe4S_Fe_S_bd_subgr.
IPR017900. 4Fe4S_Fe_S_CS.
IPR010226. NADH_quinone_OxRdtase_chainI.
[Graphical view]

Pfam

PF00037. Fer4. 2 hits.
[Graphical view]

TIGRFAMs

TIGR01971. NuoI. 1 hit.

PROSITE

PS00198. 4FE4S_FER_1. 2 hits.
PS51379. 4FE4S_FER_2. 2 hits.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

NQO9_THET8

Accession

Primary (citable) accession number: Q56224
Secondary accession number(s): Q5SM51

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1997
Last sequence update:	November 1, 1997
Last modified:	June 16, 2009
This is version 76 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes)