Protein
DNA polymerase III subunit alpha
Organism
Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / LMG 4051 / NBRC 15346 / NCIMB 9279 / R1 / VKM B-1422)
Function
DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative DNA synthesis in bacteria as well as the bulk of DNA synthesis/repair after ionizing radiation (IR) (PubMed:19303848). The alpha chain is the catalytic subunit (PubMed:19303848). Following severe irradiation (7 kGy of gamma irradiation) genomic DNA is fragmented. DNA is progressively degraded for the first 1.5 hours after IR, in a step promoted by RecA and counterbalanced by DNA Pol I and Pol III, followed by massive DNA synthesis and genome reassembly in the next hour. Optimal priming of DNA synthesis requires both RecA and RadA, Pol III initiates DNA synthesis while both Pol I and Pol III are required for its contination (PubMed:19303848). This DNA polymerase also exhibits 3' to 5' exonuclease activity (By similarity).
Similarity
Belongs to the DNA polymerase type-C family. DnaE subfamily.
Sequence
MTVSDAPTPHIHLPDGSCCQPKKFAHLHQHTQYSLLDGAAKLKDLLKWAKEVTPEGQTPALAMTDHGNMHGAVHFYNYAMGMEVKPIIGYEAYVVPGFGTRRDRSRAQDGEKGIFHLTLLARDFEGYQNLCRLSSRGYTEGYYYKPRIDHELLQEHHKGIIAFSGCLGSEVQQLLMQGREDDARARLLWYRELFGDNYFIEIQDHGLPEQKKNNPILKAWAQELGIGMVATNDGHYVKKSDATAHETLLAIQTKATLADENRFKFPCDEFYVKNLEEMQRALPVSEWGEEPFDNTAHIAELCNVELPVGKKRQYQMPQLPIPEGRSMAEELRVQTYAGAVKRYPAHLTEGLLRDYAARSLAELGEADAARVLKRTGGCDSASCDLDTLYTLLAFLGSEWEARGKEAGEKYTPYPALEKMEQDGESGTLPAYAHADCRAARRQDSDTSIELDPDTDDEETTRSHHRYALKLLRRAEYELSVINNMGFPDYFLIVADYINWAKDHDISVGPGRGSGAGSLVAYAIRITNLDPLEFELLFERFLNPDRISMPDFDIDFNDARRTEVIGYVQEKYGTDKVAQIATFGTMASKACLKDVARVMGLEYAKVDKVSKLIPIKFGKSYSLEQAREAVPDIQQMLAEDAQLLEAYEFAQKLEGLTRHASVHAAGVVIGREELTNLVPVMRDTSGEGQVCQYDMKSVEDIGLIKMDFLGLRTLSFLDEAKRILRESGTDFEEKYGDFDHIPFDDEKTYELMSRGDTKGVFQLEGAGIADASRRLKPRRLADIIALSALYRPGPMENIPTYVRRHHGIEEVDYDKDGFPNSKQWLEKILQETYGIPVYQEQIMQIASEVAGYSLGGADLLRRAMGKKDAEEMKRQRQLFVVGAKEKGVPEDEGNKLFDMLDAFANYGFNKSHSAAYGVITYQTAWLKANYPVQFMAALLTVERRDSDKVAEYVSDARKMDLHVLPPDINRSSSDFAVAGEEILFGLYAIKGLGESAVLRILEEREKAGAFKSLADFCSRLGNKVCNRKALESLIKSGAFDAFGERHQLIESLEDALEDAAGTAEINARAQSGMSMMFGMEEVKKERPLRSSIAPYSDLERLAIEKEALGLYISGHPLEQHEGLREAASCRVSDLDAWFALQNVAPGKRQKAVLAGMIEGVVKKPTKSGGMMARFILADESGQMELVAFSRAYDRIEPKLVNDTPALVIVELEAEDGGLRAIAEEIVSIEQLSEVPKVMYVTIDLETASPDALGDFQSVLDEYAGSMPTYLRLETPEQFVVYQLDHGMGSPEAIRALNQTFAWADAHLAYDQQTILGRFAPKPPAWMNRQQGGGMRA