AC   MF_01898;
DC   Protein; auto
TR   HAMAP; MF_01898; -; 1; level=0
XX
Names: GyrB
XX
ID   GYRB
DE   RecName: Full=DNA gyrase subunit B;
DE            EC=5.6.2.2;
GN   Name=gyrB;
XX
CC   -!- FUNCTION: A type II topoisomerase that negatively supercoils closed
CC       circular double-stranded (ds) DNA in an ATP-dependent manner to
CC       modulate DNA topology and maintain chromosomes in an underwound state.
CC       Negative supercoiling favors strand separation, and DNA replication,
CC       transcription, recombination and repair, all of which involve strand
CC       separation. Also able to catalyze the interconversion of other
CC       topological isomers of dsDNA rings, including catenanes and knotted
CC       rings. Type II topoisomerases break and join 2 DNA strands
CC       simultaneously in an ATP-dependent manner.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP-dependent breakage, passage and rejoining of double-
CC         stranded DNA.; EC=5.6.2.2;
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC       Name=Mn(2+); Xref=ChEBI:CHEBI:29035;
CC       Name=Ca(2+); Xref=ChEBI:CHEBI:29108;
CC       Note=Binds two Mg(2+) per subunit. The magnesium ions form salt bridges
CC       with both the protein and the DNA. Can also accept other divalent metal
CC       cations, such as Mn(2+) or Ca(2+).
CC   -!- SUBUNIT: Heterotetramer, composed of two GyrA and two GyrB chains. In
CC       the heterotetramer, GyrA contains the active site tyrosine that forms a
CC       transient covalent intermediate with DNA, while GyrB binds cofactors
CC       and catalyzes ATP hydrolysis.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm.
CC   -!- MISCELLANEOUS: Few gyrases are as efficient as E.coli at forming
CC       negative supercoils. Not all organisms have 2 type II topoisomerases;
CC       in organisms with a single type II topoisomerase this enzyme also has
CC       to decatenate newly replicated chromosomes.
CC   -!- SIMILARITY: Belongs to the type II topoisomerase GyrB family.
XX
DR   PROSITE; PS00177; TOPOISOMERASE_II; 1; trigger=no
DR   Pfam; PF00204; DNA_gyraseB; 1; trigger=no
DR   Pfam; PF00986; DNA_gyraseB_C; 1; trigger=no
DR   Pfam; PF02518; HATPase_c; 1; trigger=no
DR   Pfam; PF01751; Toprim; 0-1; trigger=no
DR   PRINTS; PR00418; TPI2FAMILY; 1; trigger=no
DR   PROSITE; PS50880; TOPRIM; 1; trigger=yes
DR   NCBIfam; TIGR01059; GyrB; 1; trigger=no
XX
KW   ATP-binding
KW   Cytoplasm
KW   Isomerase
KW   Magnesium
KW   Metal-binding
KW   Nucleotide-binding
KW   Topoisomerase
XX
GO   GO:0005524; F:ATP binding
GO   GO:0003918; F:DNA topoisomerase type II (double strand cut, ATP-hydrolyzing) activity
GO   GO:0006261; P:DNA-templated DNA replication
GO   GO:0006265; P:DNA topological change
GO   GO:0005737; C:cytoplasm
XX
FT   From: GYRB_ECOLI (P0AES6)
FT   BINDING         424
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="1"
FT                   /ligand_note="catalytic"
FT   Condition: E
FT   BINDING         498
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="1"
FT                   /ligand_note="catalytic"
FT   Condition: D
FT   BINDING         498
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT   Condition: D
FT   BINDING         500
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT   Condition: D
FT   SITE            449
FT                   /note="Interaction with DNA"
FT   Condition: K
FT   SITE            452
FT                   /note="Interaction with DNA"
FT   Condition: N
XX
Size: 632-815;
Related: None;
Template: P0AES6; P9WG45; P0A2I3; O67137;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: None
 Cter: None
Duplicate: in STRSH
Plasmid: None
Comments: The degree of DNA negative supercoiling has been studied in very
 few bacteria, E.coli gyrase is extra efficient compared to other bacteria.
 The enzyme from Aquifex aeolicus does not have the ability to negatively
 supercoil DNA as its GyrA subunit has lost the GyrA-box. Some
 Cyanobacteriota contain inteins.
XX
# Revision 1.17 2023/06/15
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