Nukleotidiltransferaza

Nukleotidiltransferaze su transferazni enzimi za grupe koje sadrže fosfor, e.g., supstituenti su nukleotidilne kiseline ili jednostavno nukleozid monofosfati. Opšta reakcija transfera nukleozid monofosfatne grupe sa A na B, se može zapisati kao:

A-P-N + B

\rightleftharpoons

A + B-P-N

Na primer, u slučaju polimeraza, A je pirofosfat i B je nascentni polinukleotid. One se klasifikuju pod EC brojem 2.7.7 i mogu se grupisati u:

Uridililtransferaze, koje prenose uridilil- grupe
Adenililtransferaze, koje prenose adenilil- grupe
Guanililtransferaze, koje prenose guanilil- grupe
Cititidililtransferaze, koje prenose citidilil- grupe
Timidililtransferaze, koje prenose timidilil- grupe

Uloga u mehanizmu DNK popravke

Nukleotidil transferaza je komponenta puta popravke pojedinačnih nukleotida isecanjem baza. Ovaj mehanizam popravke počinje kad DNK glikozilaza pepozna pojedinačni nukleotid kao nekorektno mapiran ili mutiran na neki drugi način (UV svetlost, hemijski mutagen, etc.), te ga ukloni. Zatim nukleotidil tranferaza popunjava prazninu korektnom bazom, koristeći šablonski lanac kao referencu. ^[1]

Reference

↑ Yuan Liu, Rajendra Prasad, William A. Beard, Padmini S. Kedar, Esther W. Hou, David D. Shock, and Samuel H. Wilson (May 4, 2007). „Coordination of Steps in Single-nucleotide Base Excision Repair Mediated by Apurinic/Apyrimidinic Endonuclease 1 and DNA Polymerase β”. Journal of Biological Chemistry 282 (18): 13532–13541. DOI:10.1074/jbc.M611295200. PMC 2366199. PMID 17355977. »The enzymes and accessory factors involved in the BER subpathways in mammalian cells have received considerable attention. As summarized above, five distinct enzymatic reaction are involved during SN-BER. These are 1) removal of a modified base by a lesion-specific monofunctional DNA N-glycosylase, 2) 5'-incision of the abasic site by a hydrolytic strand incision enzyme, 3) DNA synthesis by a nucleotidyltransferase, 4) removal of the 5'-dRP group by a'-elimination reaction, and 5) nick sealing by DNA ligase (36, 37)«

Vanjske veze

MeSH Nucleotidyltransferases

[1] Yuan Liu, Rajendra Prasad, William A. Beard, Padmini S. Kedar, Esther W. Hou, David D. Shock, and Samuel H. Wilson (May 4, 2007). „Coordination of Steps in Single-nucleotide Base Excision Repair Mediated by Apurinic/Apyrimidinic Endonuclease 1 and DNA Polymerase β”. Journal of Biological Chemistry 282 (18): 13532–13541. DOI:10.1074/jbc.M611295200. PMC 2366199. PMID 17355977. »The enzymes and accessory factors involved in the BER subpathways in mammalian cells have received considerable attention. As summarized above, five distinct enzymatic reaction are involved during SN-BER. These are 1) removal of a modified base by a lesion-specific monofunctional DNA N-glycosylase, 2) 5'-incision of the abasic site by a hydrolytic strand incision enzyme, 3) DNA synthesis by a nucleotidyltransferase, 4) removal of the 5'-dRP group by a'-elimination reaction, and 5) nick sealing by DNA ligase (36, 37)«

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