Q7T6X9 (TOP1E_MIMIV) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
DNA topoisomerase 1B
Short name=TopIB
EC=5.99.1.2

Alternative name(s):
DNA topoisomerase type IB

Gene names

Name:	TOP1E
Ordered Locus Names:	MIMI_R194

Organism

Acanthamoeba polyphaga mimivirus (APMV)

Taxonomic identifier

212035 [NCBI]

Taxonomic lineage

Viruses › dsDNA viruses, no RNA stage › Mimiviridae › Mimivirus

Virus host

Acanthamoeba polyphaga (Amoeba) [TaxID: 5757]

Protein attributes

Sequence length	336 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free DNA strand than undergoes passage around the unbroken strand thus removing DNA supercoils. Finally, in the religation step, the DNA 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone By similarity. Cleaves DNA after CCCTT sequence.
Catalytic activity	ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.
Subunit structure	Monomer By similarity.
Subcellular location	Virion Ref.3.
Sequence similarities	Belongs to the type IB topoisomerase family.

Ontologies

Keywords
Cellular component	Virion
Ligand	ATP-binding DNA-binding Nucleotide-binding
Molecular function	Isomerase Topoisomerase
Technical term	Complete proteome Reference proteome
Gene Ontology (GO)
Biological process	DNA topological change Inferred from electronic annotation. Source: InterPro
Cellular component	chromosome Inferred from electronic annotation. Source: InterPro virion Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	ATP binding Inferred from electronic annotation. Source: UniProtKB-KW DNA topoisomerase (ATP-hydrolyzing) activity Inferred from electronic annotation. Source: InterPro DNA topoisomerase type I activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 336	336	DNA topoisomerase 1B		PRO_0000145212
Sites
	Active site	294	1	O-(3'-phospho-DNA)-tyrosine intermediate By similarity
Experimental info
	Mutagenesis	135	1	R → A: Complete loss of supercoil relaxation activity in vitro. Ref.2
	Mutagenesis	241	1	R → A: Complete loss of supercoil relaxation activity in vitro. Ref.2
	Mutagenesis	285	1	H → A: Partial loss of supercoil relaxation activity in vitro. Ref.2
	Mutagenesis	294	1	Y → A: Complete loss of supercoil relaxation activity in vitro. Ref.2

Sequences

	Sequence		Length	Mass (Da)
	Q7T6X9 [UniParc]. Last modified December 7, 2004. Version 2. Checksum: 3C0A8CDE8D274FAB	FASTA	336	39,879
	10 20 30 40 50 60 MSYDEKHLME GIYREKSGDK FIYYYFDNNE EVTTKDIERI NKLRIPPAWT NVWVARDPNS 70 80 90 100 110 120 PIQAIGTDSK GRKQYRYNEI HIQGAEKEKF KRLYDFIKSI PKLEKAMVRD NNFPFYNKNR 130 140 150 160 170 180 VISLMLQMVR DYNMRVGKEV YARQNKSYGI SSLRKKHVKI SPGVITLNFK GKSGQRLNYT 190 200 210 220 230 240 IRNDFYIDGI KMLMKLEGDR LFQYISTDED GNEKIMRVND RDLNKYIQEN MGSEFTIKDF 250 260 270 280 290 300 RTFGANLYFI QALLSETRKR TPKNRKTIKK NIANAFKSTA RQLKHTGAVS KKSYVMNYTL 310 320 330 ELYQNNPEFF IEHKNDDPID FLLRILKSYR KDVLGE

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The 1.2-megabase genome sequence of Mimivirus." Raoult D., Audic S., Robert C., Abergel C., Renesto P., Ogata H., La Scola B., Susan M., Claverie J.-M. Science 306:1344-1350(2004) [PubMed: 15486256] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: Rowbotham-Bradford.
[2]	"Characterization of mimivirus DNA topoisomerase IB suggests horizontal gene transfer between eukaryal viruses and bacteria." Benarroch D., Claverie J.-M., Raoult D., Shuman S. J. Virol. 80:314-321(2006) [PubMed: 16352556] [Abstract] Cited for: CHARACTERIZATION, MUTAGENESIS OF ARG-135; ARG-241; HIS-285 AND TYR-294. Strain: Rowbotham-Bradford.
[3]	"Mimivirus giant particles incorporate a large fraction of anonymous and unique gene products." Renesto P., Abergel C., Decloquement P., Moinier D., Azza S., Ogata H., Fourquet P., Gorvel J.-P., Claverie J.-M., Raoult D. J. Virol. 80:11678-11685(2006) [PubMed: 16971431] [Abstract] Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS], SUBCELLULAR LOCATION.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AY653733 Genomic DNA. Translation: AAQ09581.2.
RefSeq	YP_003986690.1. NC_014649.1.
3D structure databases
ProteinModelPortal	Q7T6X9.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	9924801.
Family and domain databases
InterPro	IPR011010. DNA_brk_join_enz. IPR001631. TopoI_C. IPR014711. TopoI_cat_a-hlx-sub_euk. IPR013500. TopoI_cat_euk. IPR015346. TopoI_N_vir. [Graphical view]
Gene3D	G3DSA:3.30.66.10. G3DSA:3.30.66.10. 1 hit. G3DSA:3.90.15.10. TopoI_cat_a-hlx-sub_euk. 1 hit.
Pfam	PF01028. Topoisom_I. 1 hit. [Graphical view]
PRINTS	PR00416. EUTPISMRASEI.
SUPFAM	SSF56349. DNA_brk_join_enz. 1 hit.
PROSITE	PS00176. TOPOISOMERASE_I_EUK. False negative. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

TOP1E_MIMIV

Accession

Primary (citable) accession number: Q7T6X9

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 13, 2005
Last sequence update:	December 7, 2004
Last modified:	November 16, 2011
This is version 45 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program