REPAIRtoire - a database of DNA repair pathways

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Mgt1p (Saccharomyces cerevisiae) is product of expression of MGT1 gene.

FUNCTION: 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.

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


INDUCTION: In contrast to some bacterial and mammalian enzymes, MGT1 is not induced by alkylating agents.

MISCELLANEOUS: Present with 150 molecules/cell in log phase YPD medium, but not detectable in stationary phase cells.

MISCELLANEOUS: 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.

SIMILARITY: Belongs to the MGMT family.

SEQUENCE CAUTION: Sequence=AAA34780.1; Type=Erroneous initiation; Sequence=CAA42920.1; Type=Erroneous initiation; Sequence=CAA67469.1; Type=Erroneous initiation; Sequence=CAA98777.1; Type=Erroneous initiation; Sequence=CAA98778.1; Type=Erroneous initiation;

NCBI GenPept GI number(s): 1431330
Species: Saccharomyces cerevisiae

Links to other databases:

Database ID Link
Uniprot P26188 P26188
PFAM: - P26188 (Link - using uniprot id)
InterPro: IPR001497
CATH: - -
SCOP: - -
PDB: - -

Protein sequence:


Title Authors Journal
Identification and preliminary characterization of an O6-methylguanine DNA repair methyltransferase in the yeast Saccharomyces cerevisiae. Sassanfar M, Samson L J Biol Chem Feb. 5, 1990
Relative efficiencies of the bacterial, yeast, and human DNA methyltransferases for the repair of O6-methylguanine and O4-methylthymine. Suggestive evidence for O4-methylthymine repair by eukaryotic methyltransferases. Sassanfar M, Dosanjh MK, Essigmann JM, Samson L J Biol Chem Jan. 15, 1991
Primary sequence and biological functions of a Saccharomyces cerevisiae O6-methylguanine/O4-methylthymine DNA repair methyltransferase gene. Xiao W, Derfler B, Chen J, Samson L EMBO J Aug. 1, 1991
The Saccharomyces cerevisiae MGT1 DNA repair methyltransferase gene: its promoter and entire coding sequence, regulation and in vivo biological functions. Xiao W, Samson L Nucleic Acids Res July 25, 1992
Expression of yeast O6-methylguanine-DNA methyltransferase (MGMT) gene. Joo JH, Rho JK, Kim JH, Kim WJ, Choe SY, Park SD Cell Mol Biol (Noisy-le-grand) June 1, 1995
The sequence of 23 kb surrounding the SNF3 locus on the left arm of yeast chromosome IV reveals the location of five known genes and characterizes at least six new open reading frames including putative genes for ribosomal protein L35 and a sugar transport protein. Verhasselt P, Voet M, Mathys J, Volckaert G Yeast Sept. 1, 1996
The nucleotide sequence of a 39 kb segment of yeast chromosome IV: 12 new open reading frames, nine known genes and one genes for Gly-tRNA. Bahr A, Moller-Rieker S, Hankeln T, Kraemer C, Protin U, Schmidt ER Yeast Jan. 1, 1997
The nucleotide sequence of Saccharomyces cerevisiae chromosome IV. Jacq C, Alt-Morbe J, Andre B, Arnold W, Bahr A, Ballesta JP, Bargues M, Baron L, Becker A, Biteau N, Blocker H, Blugeon C, Boskovic J, Brandt P, Bruckner M, Buitrago MJ, Coster F, Delaveau T, del Rey F, Dujon B, Eide LG, Garcia-Cantalejo JM, Goffeau A, Gomez-Peris A, Zaccaria P, et al. Nature May 1, 1997
Sequencing and comparison of yeast species to identify genes and regulatory elements. Kellis M, Patterson N, Endrizzi M, Birren B, Lander ES Nature May 15, 2003
Finding functional features in Saccharomyces genomes by phylogenetic footprinting. Cliften P, Sudarsanam P, Desikan A, Fulton L, Fulton B, Majors J, Waterston R, Cohen BA, Johnston M Science July 4, 2003

Last modification of this entry: Oct. 6, 2010.

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