title: The metG gene of Aspergillus nidulans encoding cystathionine beta-lyase: cloning and analysis.
abstract: The metG gene of Aspergillus nidulans encoding cystathionine beta-lyase, an enzyme of the main pathway of methionine synthesis, was cloned by complementation of a metG mutation. A comparison of metG genomic DNA and a cDNA copy derived from different A. nidulans strains revealed a marked DNA sequence polymorphism manifested mostly by silent point mutations. cDNA of the A. nidulans metG gene complemented the Escherichia coli metC69 mutation impairing cystathionine beta-lyase. This gene contains two introns and codes for a protein of 439 amino acids. The protein shows homology with bacterial, yeast and plant cystathionine beta-lyases, as well as with other enzymes belonging to a large family of pyridoxal 5'-phosphate binding proteins. Transcription of the metG gene is not appreciably regulated by the concentration of sulphur source in the growth medium.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5 a, PL-02-106 Warsaw, Poland. apasz@ibbrain.ibb.waw.pl
authors.forename: M
authors.initials: M
authors.lastname: Sieńko
authors.forename: A
authors.initials: A
authors.lastname: Paszewski
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics*; D008190:Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D004271:DNA, Fungal; D008190:Lyases; C019965:cystathionine beta-lyase