Homo sapiens L. (human) [HSA]

FULL NAME: DNA-(apurinic or apyrimidinic site) lyase 2


DESCRIPTION:
Function as a weak apurinic/apyrimidinic (AP) endodeoxyribonuclease in the DNA base excision repair (BER) pathway of DNA lesions induced by oxidative and alkylating agents. Initiates repair of AP sites in DNA by catalyzing hydrolytic incision of the phosphodiester backbone immediately adjacent to the damage, generating a single-strand break with 5'-deoxyribose phosphate and 3'-hydroxyl ends. Displays also double-stranded DNA 3'-5' exonuclease, 3'-phosphodiesterase activities. Shows robust 3'-5' exonuclease activity on 3'-recessed heteroduplex DNA and is able to remove mismatched nucleotides preferentially. Shows fairly strong 3'-phosphodiesterase activity involved in the removal of 3'-damaged termini formed in DNA by oxidative agents. In the nucleus functions in the PCNA-dependent BER pathway. Required for somatic hypermutation (SHM) and DNA cleavage step of class switch recombination (CSR) of immunoglobulin genes. Required for proper cell cycle progression during proliferation of peripheral lymphocytes.

STRUCTURE SIMILARITY:
Belongs to the DNA repair enzymes AP/ExoA family.


CATALYTIC ACTIVITY:
The C-O-P bond 3' to the apurinic or apyrimidinic site in DNA is broken by a beta-elimination reaction, leaving a 3'-terminal unsaturated sugar and a product with a terminal 5'-phosphate.


ENZYME REGULATION:
3'-5' exonuclease activity is activated by sodium and manganese. 3'-5' exonuclease and 3'-phosphodiesterase activities are stimulated in presence of PCNA.


RELATED PATHWAY(S):
base excision repair (BER)


RELATED DAMAGE:
3'-OH end
3'-P
3'-PUA termini
AP-site


Amino acids sequence

        10         20         30         40         50         60
MLRVVSWNIN GIRRPLQGVA NQEPSNCAAV AVGRILDELD ADIVCLQETK VTRDALTEPL
        70         80         90        100        110        120
AIVEGYNSYF SFSRNRSGYS GVATFCKDNA TPVAAEEGLS GLFATQNGDV GCYGNMDEFT
       130        140        150        160        170        180
QEELRALDSE GRALLTQHKI RTWEGKEKTL TLINVYCPHA DPGRPERLVF KMRFYRLLQI
       190        200        210        220        230        240
RAEALLAAGS HVIILGDLNT AHRPIDHWDA VNLECFEEDP GRKWMDSLLS NLGCQSASHV
       250        260        270        280        290        300
GPFIDSYRCF QPKQEGAFTC WSAVTGARHL NYGSRLDYVL GDRTLVIDTF QASFLLPEVM
       310        320        330        340        350        360
GSDHCPVGAV LSVSSVPAKQ CPPLCTRFLP EFAGTQLKIL RFLVPLEQSP VLEQSTLQHN
       370        380        390        400        410        420
NQTRVQTCQN KAQVRSTRPQ PSQVGSSRGQ KNLKSYFQPS PSCPQASPDI ELPSLPLMSA
       430        440        450        460        470        480
LMTPKTPEEK AVAKVVKGQA KTSEAKDEKE LRTSFWKSVL AGPLRTPLCG GHREPCVMRT
       490        500        510
VKKPGPNLGR RFYMCARPRG PPTDPSSRCN FFLWSRPS  

Encoded by APEX2 gene

FULL NAME: APEX nuclease (apurinic/apyrimidinic endonuclease) 2


OTHER NAME(S):
APE2
APEXL2
XTH2


DESCRIPTION:
Apurinic/apyrimidinic (AP) sites occur frequently in DNA molecules by spontaneous hydrolysis, by DNA damaging agents or by DNA glycosylases that remove specific abnormal bases. AP sites are pre-mutagenic lesions that can prevent normal DNA replication so the cell contains systems to identify and repair such sites. Class II AP endonucleases cleave the phosphodiester backbone 5' to the AP site. This gene encodes a protein shown to have a weak class II AP endonuclease activity. Most of the encoded protein is located in the nucleus but some is also present in mitochondria. This protein may play an important role in both nuclear and mitochondrial base excision repair (BER). [provided by RefSeq, Jul 2008]


Nucleic acid sequence

        10         20         30         40         50         60
atgttgcgcg tggtgagctg gaacatcaat gggattcgga gacccctgca aggggtggca
        70         80         90        100        110        120
aatcaggaac ccagcaactg tgccgccgtg gccgtggggc gcattttgga cgagctggat
       130        140        150        160        170        180
gcggatatcg tctgtctcca ggaaaccaaa gtgaccaggg atgcactgac agagcccctg
       190        200        210        220        230        240
gctatcgttg agggttataa ctcctatttc agcttcagcc gcaaccgtag cggctattct
       250        260        270        280        290        300
ggtgtagcca ccttctgtaa ggacaatgct accccagtgg ctgctgaaga aggcctgagt
       310        320        330        340        350        360
ggcctgtttg ccacccagaa tggggatgtt ggttgctatg gaaacatgga tgagtttacc
       370        380        390        400        410        420
caagaggaac tccgggctct ggatagtgag ggcagggccc tcctcacaca gcataagatc
       430        440        450        460        470        480
cgcacatggg aaggtaagga gaagaccttg accctaatca acgtgtactg cccccatgcg
       490        500        510        520        530        540
gaccctggga ggcctgagcg gctagtcttt aagatgcgct tctatcgttt gctgcaaatc
       550        560        570        580        590        600
cgagcagaag ccctcctggc ggcaggcagc catgtgatca ttctgggtga cctgaataca
       610        620        630        640        650        660
gcccaccgcc ccattgacca ctgggatgca gtcaacctgg aatgctttga agaggaccca
       670        680        690        700        710        720
gggcgcaagt ggatggacag cttgctcagt aacttggggt gccagtctgc ctctcatgta
       730        740        750        760        770        780
gggcccttca tcgatagcta ccgctgcttc caaccaaagc aggagggggc cttcacctgc
       790        800        810        820        830        840
tggtcagcag tcactggcgc ccgccatctc aactatggct cccggcttga ctatgtgctg
       850        860        870        880        890        900
ggggacagga ccctggtcat agacaccttt caggcctctt tcctgctgcc tgaggtgatg
       910        920        930        940        950        960
ggctctgacc actgccctgt gggtgcagtc ttgagtgtgt cctctgtgcc tgcaaaacag
       970        980        990       1000       1010       1020
tgcccacctc tgtgcacccg cttcctccct gagtttgcag gcacccagct caagatcctt
      1030       1040       1050       1060       1070       1080
cgcttcctag ttcctctcga acaaagtcct gtgttggagc agtcgacgct gcagcacaac
      1090       1100       1110       1120       1130       1140
aatcaaaccc gggtacagac atgccaaaac aaagcccaag tgcgctcaac caggcctcag
      1150       1160       1170       1180       1190       1200
cccagtcagg ttggctctag cagaggccag aaaaacctga agagctactt tcagccctcc
      1210       1220       1230       1240       1250       1260
cctagctgtc cccaagcctc tcctgacata gagctgccta gcctaccact gatgagcgcc
      1270       1280       1290       1300       1310       1320
ctcatgaccc cgaagactcc agaagagaag gcagtggcca aagtggtgaa ggggcaggcc
      1330       1340       1350       1360       1370       1380
aagacttcag aagccaaaga tgagaaggag ttacggacct cattctggaa gtctgtgctg
      1390       1400       1410       1420       1430       1440
gcggggccct tgcgcacacc cctctgtggg ggccacaggg agccatgtgt gatgcgtact
      1450       1460       1470       1480       1490       1500
gtgaagaagc caggacccaa cttgggccgc cgcttctaca tgtgtgccag gccccggggt
      1510       1520       1530       1540       1550
cctcccactg acccctcctc ccggtgcaac ttcttcctct ggagcaggcc cagctga

Last modification date: Oct. 2, 2011