ID   GYRA_STRNV              Reviewed;          21 AA.
AC   P50071;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   25-MAY-2022, entry version 49.
DE   RecName: Full=DNA gyrase subunit A {ECO:0000255|HAMAP-Rule:MF_01897};
DE            EC=5.6.2.2 {ECO:0000255|HAMAP-Rule:MF_01897};
DE   Flags: Fragment;
GN   Name=gyrA {ECO:0000255|HAMAP-Rule:MF_01897};
OS   Streptomyces niveus (Streptomyces spheroides).
OC   Bacteria; Actinobacteria; Streptomycetales; Streptomycetaceae;
OC   Streptomyces.
OX   NCBI_TaxID=193462;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ATCC 23965 / DSM 40292 / JCM 4252 / NBRC 12917 / NCIMB 11891 / NRRL
RC   2449;
RX   PubMed=8392138; DOI=10.1111/j.1365-2958.1993.tb01593.x;
RA   Thiara A.S., Cundliffe E.;
RT   "Expression and analysis of two gyrB genes from the novobiocin producer,
RT   Streptomyces sphaeroides.";
RL   Mol. Microbiol. 8:495-506(1993).
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. {ECO:0000255|HAMAP-
CC       Rule:MF_01897}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP-dependent breakage, passage and rejoining of double-
CC         stranded DNA.; EC=5.6.2.2; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_01897};
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. {ECO:0000255|HAMAP-Rule:MF_01897}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_01897,
CC       ECO:0000305}.
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. {ECO:0000255|HAMAP-
CC       Rule:MF_01897}.
CC   -!- SIMILARITY: Belongs to the type II topoisomerase GyrA/ParC subunit
CC       family. {ECO:0000255|HAMAP-Rule:MF_01897}.
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DR   EMBL; Z17305; CAA78953.1; -; Genomic_DNA.
DR   PIR; S32883; S32883.
DR   AlphaFoldDB; P50071; -.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-KW.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003918; F:DNA topoisomerase type II (double strand cut, ATP-hydrolyzing) activity; IEA:UniProtKB-EC.
PE   3: Inferred from homology;
KW   ATP-binding; Cytoplasm; DNA-binding; Isomerase; Nucleotide-binding;
KW   Topoisomerase.
FT   CHAIN           1..>21
FT                   /note="DNA gyrase subunit A"
FT                   /id="PRO_0000145268"
FT   REGION          1..21
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   NON_TER         21
SQ   SEQUENCE   21 AA;  2202 MW;  5E2F9DEA8DB83697 CRC64;
     MADENTPVMP EEVPAVEGVG M