Saccharomyces cerevisiae Meyen ex E.C. Hansen (budding yeast) [SCE]

FULL NAME: Methylated-DNA--protein-cysteine methyltransferase


DESCRIPTION:
Involved in the cellular defense against the biological effects of O6-methylguanine (O6-MeG) in DNA. Repairs alkylated guanine in DNA by stoichiometrically transferring the alkyl group at the O-6 position to a cysteine residue in the enzyme. This is a suicide reaction: the enzyme is irreversibly inactivated. Also repairs O-4-methylthymine. Prefers double-stranded DNA over single-stranded DNA as subtsrate.

MISCELLANEOUS:
Present with 150 molecules/cell in log phase YPD medium, but not detectable in stationary phase cells.
This enzyme catalyzes only one turnover and therefore is not strictly catalytic. According to one definition, an enzyme is a biocytalyst that acts repeatedly and over many reaction cycles.


STRUCTURE SIMILARITY:
Belongs to the MGMT family.


CATALYTIC ACTIVITY:
DNA (containing 6-O-methylguanine) + protein L-cysteine = DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine.


RELATED PATHWAY(S):
direct reversal (DR)


Amino acids sequence

        10         20         30         40         50         60
MKELLYYTFI ETEVTGAFLV FREKTQNLVF ASLGNDKLFL LGKVEGFLKK HEKQDTMYDL
        70         80         90        100        110        120
QELKEAETYK KSIENYTICL ENKMPLPSGA IPFEFLFGTD FQRKVWNELL NVEHGHVVTY
       130        140        150        160        170        180
GDIAKRIGKP TAARSVGRAC GSNNLALLVP CHRIVGSNRK LTGYKWSCKL KEQLLNNEKE

NSLSLSRL     

Encoded by MGT1 gene


Nucleic acid sequence

        10         20         30         40         50         60
atgaaggaac tgctttacta tacattcatt gaaactgaag tgactggtgc atttttggtg
        70         80         90        100        110        120
tttagggaaa agactcaaaa ccttgttttt gcctcgttag gtaatgataa gcttttttta
       130        140        150        160        170        180
ttgggaaagg tggaaggctt cttgaagaaa catgagaaac aggatacaat gtacgattta
       190        200        210        220        230        240
caggaactaa aagaggcaga aacatataag aaatcaatcg aaaattatac aatatgttta
       250        260        270        280        290        300
gaaaacaaaa tgccattacc atcgggcgct attccctttg agttcctgtt tggaacagat
       310        320        330        340        350        360
tttcaacgta aagtttggaa tgagctttta aacgtggaac acggccacgt cgtaacatat
       370        380        390        400        410        420
ggtgatattg caaagagaat agggaagcca actgccgcaa gatctgtcgg aagagcttgc
       430        440        450        460        470        480
ggctcaaata acctggcatt gttagtacct tgccatagaa tcgttggtag caatagaaaa
       490        500        510        520        530        540
ttaaccggat ataaatggag ctgtaaactg aaagaacagt tattaaataa tgaaaaggaa
       550        560
aatagcttaa gccttagtag attgtag   

Last modification date: Oct. 2, 2011