Q56218 (NQO6_THET8) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
NADH-quinone oxidoreductase subunit 6
EC=1.6.99.5

Alternative name(s):
NADH dehydrogenase I subunit 6
NDH-1 subunit 6

Gene names

Name:	nqo6
Ordered Locus Names:	TTHA0085

Organism

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

Taxonomic identifier

300852 [NCBI]

Taxonomic lineage

cellular organisms › Bacteria › Deinococcus-Thermus › Deinococci › Thermales › Thermaceae › Thermus › Thermus thermophilus

Protein attributes

Sequence length	181 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
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. HAMAP-Rule MF_01356
Catalytic activity	NADH + quinone = NAD+ + quinol. HAMAP-Rule MF_01356
Cofactor	Binds 1 4Fe-4S cluster per subunit. This 4Fe-4S cluster is referred to as N2.
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. Subunit nqo6 interacts extensively with nqo4. Ref.3 Ref.4
Subcellular location	Cell membrane; Peripheral membrane protein; Cytoplasmic side HAMAP-Rule MF_01356.
Sequence similarities	Belongs to the complex I 20 kDa subunit family.

Ontologies

Keywords
Cellular component	Cell membrane Membrane
Ligand	4Fe-4S Iron Iron-sulfur Metal-binding NAD
Molecular function	Oxidoreductase
PTM	Quinone
Technical term	3D-structure Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological_process	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 (ubiquinone) 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

Initiator methionine

1

1

Removed Ref.3

Chain

2 – 181

180

NADH-quinone oxidoreductase subunit 6 HAMAP-Rule MF_01356

PRO_0000118763

Sites

Metal binding

45

1

Iron-sulfur (4Fe-4S)

Metal binding

46

1

Iron-sulfur (4Fe-4S)

Metal binding

111

1

Iron-sulfur (4Fe-4S)

Metal binding

140

1

Iron-sulfur (4Fe-4S)

Secondary structure

1

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181

Helix Strand Turn

Details...

Helix

19 – 32

14

Beta strand

39 – 42

4

Helix

46 – 50

5

Turn

51 – 56

6

Helix

72 – 74

3

Beta strand

78 – 82

5

Turn

86 – 88

3

Helix

89 – 97

9

Beta strand

105 – 108

4

Helix

109 – 113

5

Beta strand

120 – 123

4

Helix

127 – 129

3

Beta strand

134 – 137

4

Beta strand

139 – 141

3

Helix

144 – 158

15

Beta strand

159 – 161

3

Beta strand

165 – 167

3

Beta strand

176 – 178

3

Sequences

	Sequence		Length	Mass (Da)
	Q56218 [UniParc]. Last modified January 23, 2007. Version 3. Checksum: A1E030366E6692F1	FASTA	181	20,239
	10 20 30 40 50 60 MALKDLFERD VQELEREGIL FTTLEKLVAW GRSNSLWPAT FGLACCAIEM MASTDARNDL 70 80 90 100 110 120 ARFGSEVFRA SPRQADVMIV AGRLSKKMAP VMRRVWEQMP DPKWVISMGA CASSGGMFNN 130 140 150 160 170 180 YAIVQNVDSV VPVDVYVPGC PPRPEALIYA VMQLQKKVRG QAYNERGERL PPVAAWKRTR G

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] [Europe PMC] [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]. Strain: HB8 / ATCC 27634 / DSM 579.
[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] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 2-9, IDENTIFICATION BY MASS SPECTROMETRY, EPR SPECTROSCOPY, 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] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (3.3 ANGSTROMS), SUBUNIT, ELECTRON TRANSFER MECHANISM.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

U52917 Genomic DNA. Translation: AAA97939.1.
AP008226 Genomic DNA. Translation: BAD69908.1.

PIR

T11899.

RefSeq

YP_143351.1. NC_006461.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2FUG	X-ray	3.30	6/F/O/X	1-181	[»]
2YBB	electron microscopy	19.00	6	1-181	[»]
3I9V	X-ray	3.10	6/F	1-181	[»]
3IAM	X-ray	3.10	6/F	1-181	[»]
3IAS	X-ray	3.15	6/F/O/X	1-181	[»]
3M9S	X-ray	4.50	6/F	1-181	[»]
4HEA	X-ray	3.30	6/G	1-181	[»]

ProteinModelPortal

Q56218.

SMR

Q56218. Positions 15-175.

ModBase

Search...

Protein-protein interaction databases

DIP

DIP-59264N.

STRING

300852.TTHA0085.

Protein family/group databases

TCDB

3.D.1.3.1. H+ or Na+-translocating NADH dehydrogenase (NDH) family.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblBacteria

BAD69908; BAD69908; BAD69908.

GeneID

3168381.

KEGG

ttj:TTHA0085.

PATRIC

23955101. VBITheThe93045_0083.

Phylogenomic databases

eggNOG

COG0377.

HOGENOM

HOG000228249.

KO

K00331.

OMA

INYTRTG.

ProtClustDB

PRK06411.

Family and domain databases

Gene3D

3.40.50.700. 1 hit.

HAMAP

MF_01356. NDH1_NuoB.

InterPro

IPR006137. NADH_UbQ_OxRdtase-like_20kDa.
IPR006138. NADH_UQ_OxRdtase_20Kd_su.
IPR014406. NiFe-hyd_3_ssu/Q_oxred_NuoB.
[Graphical view]

PANTHER

PTHR11995. PTHR11995. 1 hit.

Pfam

PF01058. Oxidored_q6. 1 hit.
[Graphical view]

TIGRFAMs

TIGR01957. nuoB_fam. 1 hit.

PROSITE

PS01150. COMPLEX1_20K. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

Q56218.

Entry information

Entry name

NQO6_THET8

Accession

Primary (citable) accession number: Q56218
Secondary accession number(s): Q5SM58

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1997
Last sequence update:	January 23, 2007
Last modified:	May 1, 2013
This is version 95 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program