Homo sapiens L. (human) [HSA]

FULL NAME: DNA topoisomerase I, mitochondrial


DESCRIPTION:
Relieves DNA strain that arise during duplication of mitochondrial DNA.
Relieves DNA strain that arise during duplication of mitochondrial DNA. When a topoisomerase transiently breaks a DNA backbone bond, it simultaneously forms a protein-DNA link, in which a tyrosyl oxygen in the enzyme is joined to a DNA phosphorus at one end of the enzyme-severed DNA strand. The N-terminal domain of TOP1MT contains a mitochondrial localization sequence and lacks a nuclear localization signal. The pattern of TOP1MT expression matches the requirement for high mitochondrial activity in specific tissues. TOP1MT is a type IB topoisomerase and requires divalent metal, Ca(2+) or Mg(2+), and alkaline pH for optimal activity. TOP1MT gene contains 14 exons.

Tension generated in the circular mitochondrial genome during replication and transcription points to the need for mitochondrial DNA topoisomerase activity (Zhang et al., 2001).

MISCELLANEOUS:
When a topoisomerase transiently breaks a DNA backbone bond, it simultaneously forms a protein-DNA link, in which a tyrosyl oxygen in the enzyme is joined to a DNA phosphorus at one end of the enzyme-severed DNA strand.


STRUCTURE SIMILARITY:
Belongs to the eukaryotic type I topoisomerase family.


CATALYTIC ACTIVITY:
ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.


PROTEIN TYPE(S):
endonuclease
DNA topoisomerase


RELATED PATHWAY(S):
DNA replication


Amino acids sequence

        10         20         30         40         50         60
MRVVRLLRLR AALTLLGEVP RRPASRGVPG SRRTQKGSGA RWEKEKHEDG VKWRQLEHKG
        70         80         90        100        110        120
PYFAPPYEPL PDGVRFFYEG RPVRLSVAAE EVATFYGRML DHEYTTKEVF RKNFFNDWRK
       130        140        150        160        170        180
EMAVEEREVI KSLDKCDFTE IHRYFVDKAA ARKVLSREEK QKLKEEAEKL QQEFGYCILD
       190        200        210        220        230        240
GHQEKIGNFK IEPPGLFRGR GDHPKMGMLK RRITPEDVVI NCSRDSKIPE PPAGHQWKEV
       250        260        270        280        290        300
RSDNTVTWLA AWTESVQNSI KYIMLNPCSK LKGETAWQKF ETARRLRGFV DEIRSQYRAD
       310        320        330        340        350        360
WKSREMKTRQ RAVALYFIDK LALRAGNEKE DGEAADTVGC CSLRVEHVQL HPEADGCQHV
       370        380        390        400        410        420
VEFDFLGKDC IRYYNRVPVE KPVYKNLQLF MENKDPRDDL FDRLTTTSLN KHLQELMDGL
       430        440        450        460        470        480
TAKVFRTYNA SITLQEQLRA LTRAEDSIAA KILSYNRANR VVAILCNHQR ATPSTFEKSM
       490        500        510        520        530        540
QNLQTKIQAK KEQVAEARAE LRRARAEHKA QGDGKSRSVL EKKRRLLEKL QEQLAQLSVQ
       550        560        570        580        590        600
ATDKEENKQV ALGTSKLNYL DPRISIAWCK RFRVPVEKIY SKTQRERFAW ALAMAGEDFE

F     

Encoded by TOP1MT gene

FULL NAME: topoisomerase (DNA) I, mitochondrial


DESCRIPTION:
This gene encodes a mitochondrial DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This enzyme catalyzes the transient breaking and rejoining of DNA which allows the strands to pass through one another and relieves the stress introduced by a circular mitochondrial genome during replication and transcription. [provided by RefSeq, Jul 2008]


Nucleic acid sequence

        10         20         30         40         50         60
atgcgcgtgg tgcggctgct gcggctccgg gcggctctga cgctgctcgg ggaggtcccc
        70         80         90        100        110        120
cgccgcccgg cctcccgggg tgtcccgggc tcgcgcagga cgcagaaggg cagtggagcc
       130        140        150        160        170        180
aggtgggaga aggagaagca cgaagacggg gtgaagtgga gacagctgga gcacaagggc
       190        200        210        220        230        240
ccgtacttcg cacccccata cgagcccctt cccgacggag tgcgtttctt ctatgaagga
       250        260        270        280        290        300
aggcctgtga gattgagcgt ggcagcggag gaggtcgcca ctttttatgg gaggatgtta
       310        320        330        340        350        360
gatcatgaat acacaacaaa ggaggttttc cggaagaact tcttcaatga ctggcgaaag
       370        380        390        400        410        420
gaaatggcgg tggaagagag ggaagtcatc aagagcctgg acaagtgtga cttcacggag
       430        440        450        460        470        480
atccacagat actttgtgga caaggccgca gcccggaaag tcctgagcag ggaggagaag
       490        500        510        520        530        540
cagaagctaa aagaagaggc agaaaaactt cagcaagagt tcggctactg tattttagat
       550        560        570        580        590        600
ggtcaccaag aaaaaatagg caacttcaag attgagccgc ctggcttgtt ccgtggccgt
       610        620        630        640        650        660
ggcgaccatc ccaagatggg gatgctgaag agaaggatca cgccagagga tgtggttatc
       670        680        690        700        710        720
aactgcagca gggactcgaa gatccccgag ccgccggcgg ggcaccagtg gaaggaggtg
       730        740        750        760        770        780
cgctccgata acaccgtcac gtggctggca gcttggaccg agagcgttca gaactccatc
       790        800        810        820        830        840
aagtacatca tgctgaaccc ttgctcgaag ctgaaggggg agacagcttg gcagaagttt
       850        860        870        880        890        900
gaaacagctc gacgcctgcg gggatttgtg gacgagatcc gctcccagta ccgggctgac
       910        920        930        940        950        960
tggaagtctc gggaaatgaa gacgagacag cgggcggtgg ccctgtattt catcgataag
       970        980        990       1000       1010       1020
ctggcactga gagcaggaaa tgagaaggag gacggtgagg cggccgacac cgtgggctgc
      1030       1040       1050       1060       1070       1080
tgttccctcc gcgtggagca cgtccagctg cacccggagg ccgatggctg ccaacacgtg
      1090       1100       1110       1120       1130       1140
gtggaatttg acttcctggg gaaggactgc atccgctact acaacagagt gccggtggag
      1150       1160       1170       1180       1190       1200
aagccggtgt acaagaactt acagctcttt atggagaaca aggacccccg ggacgacctc
      1210       1220       1230       1240       1250       1260
ttcgacaggc tgaccacgac cagcctgaac aagcacctcc aggagctgat ggacgggctg
      1270       1280       1290       1300       1310       1320
acggccaagg tgttccggac ctacaacgcc tccatcactc tgcaggagca gctgcgggcc
      1330       1340       1350       1360       1370       1380
ctgacgcgcg ccgaggacag catagcagct aagatcttat cctacaaccg agccaaccga
      1390       1400       1410       1420       1430       1440
gtcgtggcca ttctctgcaa ccatcagcga gcaaccccca gtacgttcga gaagtcgatg
      1450       1460       1470       1480       1490       1500
cagaatctcc agacgaagat ccaggcaaag aaggagcagg tggctgaggc cagggcagag
      1510       1520       1530       1540       1550       1560
ctgaggaggg cgagggctga gcacaaagcc caaggggatg gcaagtccag gagtgtcctg
      1570       1580       1590       1600       1610       1620
gagaagaaga ggcggctcct ggagaagctg caggagcagc tggcgcagct gagtgtgcag
      1630       1640       1650       1660       1670       1680
gccacggaca aggaggagaa caagcaggtg gccctgggca cgtccaagct caactacctg
      1690       1700       1710       1720       1730       1740
gaccccagga tcagcattgc ctggtgcaag cggttcaggg tgccagtgga gaagatctac
      1750       1760       1770       1780       1790       1800
agcaaaacac agcgggagag gttcgcctgg gctctcgcca tggcaggaga agactttgaa

ttctaa     

Last modification date: Oct. 2, 2011