Sieńko M, Paszewski A
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5 a, PL-02-106 Warsaw, Poland.
Curr Genet. 1999 Jul;35(6):638-46. doi: 10.1007/s002940050463.
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.
通过对构巢曲霉metG突变的互补作用，克隆了构巢曲霉中编码胱硫醚β-裂解酶（蛋氨酸合成主要途径中的一种酶）的metG基因。对来自不同构巢曲霉菌株的metG基因组DNA和cDNA拷贝进行比较，发现了明显的DNA序列多态性，主要表现为沉默点突变。构巢曲霉metG基因的cDNA补充了大肠杆菌中损害胱硫醚β-裂解酶的metC69突变。该基因包含两个内含子，编码一个由439个氨基酸组成的蛋白质。该蛋白质与细菌、酵母和植物的胱硫醚β-裂解酶以及属于磷酸吡哆醛结合蛋白大家族的其他酶具有同源性。metG基因的转录不受生长培养基中硫源浓度的明显调节。
