AC   MF_00952;
DC   Protein; auto
TR   HAMAP; MF_00952; -; 1; level=0
XX
Names: Topoisom_1_prok
XX
ID   TOP1
DE   RecName: Full=DNA topoisomerase 1;
DE            EC=5.6.2.1;
DE   AltName: Full=DNA topoisomerase I;
GN   Name=topA;
XX
CC   -!- FUNCTION: Releases the supercoiling and torsional tension of DNA, which
CC       is introduced during the DNA replication and transcription, by
CC       transiently cleaving and rejoining one strand of the DNA duplex.
CC       Introduces a single-strand break via transesterification at a target
CC       site in duplex DNA. The scissile phosphodiester is attacked by the
CC       catalytic tyrosine of the enzyme, resulting in the formation of a DNA-
CC       (5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH
CC       DNA strand. The free DNA strand then undergoes passage around the
CC       unbroken strand, thus removing DNA supercoils. Finally, in the
CC       religation step, the DNA 3'-OH attacks the covalent intermediate to
CC       expel the active-site tyrosine and restore the DNA phosphodiester
CC       backbone.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP-independent breakage of single-stranded DNA, followed by
CC         passage and rejoining.; EC=5.6.2.1;
CC   -!- SUBUNIT: Monomer.
CC   -!- SIMILARITY: Belongs to the type IA topoisomerase family.
XX
DR   PROSITE; PS00396; TOPO_IA_1; 1; trigger=no
DR   PROSITE; PS52039; TOPO_IA_2; 1; trigger=yes
DR   PROSITE; PS50880; TOPRIM; 1; trigger=yes
DR   Pfam; PF08272; Topo_Zn_Ribbon; 0-2; trigger=no
DR   Pfam; PF01131; Topoisom_bac; 1; trigger=no
DR   Pfam; PF01751; Toprim; 1; trigger=no
DR   Pfam; PF01396; zf-C4_Topoisom; 0-3; trigger=no
DR   PRINTS; PR00417; PRTPISMRASEI; 1; trigger=no
DR   NCBIfam; TIGR01051; topA_bact; 0-1; trigger=no
DR   NCBIfam; TIGR01057; topA_arch; 0-1; trigger=no
XX
KW   DNA-binding
KW   Isomerase
KW   Topoisomerase
XX
GO   GO:0003917; F:DNA topoisomerase type I (single strand cut, ATP-independent) activity
GO   GO:0006265; P:DNA topological change
XX
FT   From: TOP1_ECOLI (P06612)
FT   REGION          192..197
FT                   /note="Interaction with DNA"
FT   Optional; Condition: S-x-G-R-V-Q
FT   ACT_SITE        319
FT                   /note="O-(5'-phospho-DNA)-tyrosine intermediate"
FT   Condition: Y
FT   SITE            33
FT                   /note="Interaction with DNA"
FT   Optional; Condition: H
FT   SITE            168
FT                   /note="Interaction with DNA"
FT   Optional; Condition: R
FT   SITE            169
FT                   /note="Interaction with DNA"
FT   Optional; Condition: R
FT   SITE            172
FT                   /note="Interaction with DNA"
FT   Optional; Condition: D
FT   SITE            177
FT                   /note="Interaction with DNA"
FT   Optional; Condition: Y
FT   SITE            184
FT                   /note="Interaction with DNA"
FT   Optional; Condition: W
FT   SITE            321
FT                   /note="Interaction with DNA"
FT   Optional; Condition: R
FT   SITE            507
FT                   /note="Interaction with DNA"
FT   Optional; Condition: R
XX
Size: 560-1100;
Related: None;
Template: P06612; P9WG49;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: None
 Cter: None
Duplicate: in XYLFA
Plasmid: in XYLFA
Comments: None
XX
# Revision 1.11 2023/10/10
//