Filutowicz M, Cieśla Z, Kłopotowski T
J Gen Microbiol. 1979 Jul;113(1):45-55. doi: 10.1099/00221287-113-1-45.
The growth inhibition of Salmonella typhimurium aziA mutants by sodium azide is reversed by cystine and related compounds. NADPH-sulphite reductase (hydrogen-sulphide:NADP+ oxidoreductase; EC 1.8.1.2), an enzyme of cysteine biosynthesis, is inhibited in cell extracts by sodium azide. AziB mutants which are able to grow in the presence of the inhibitor without cystine were isolated. About half of them were mapped in the cysK gene and have only residual activity of its product, O-acetylserine sulphydrylase A [O-acetyl-L-serine acetate-lyase (adding hydrogen-sulphide); EC 4.2.99.8]. Sensitivity of wild type and aziA mutants to azide was also reversed by a constitutive mutation in cysB, the regulatory gene of cysteine biosynthesis. CysK and cysB mutants showed cross-resistance to azide and 1,2,4-triazole. It is suggested that the resistance of these mutants to azide is due to an increased activity of NADPH-sulphite reductase.
叠氮钠对鼠伤寒沙门氏菌aziA突变体的生长抑制作用可被胱氨酸及相关化合物逆转。NADPH-亚硫酸盐还原酶（硫化氢：NADP+氧化还原酶；EC 1.8.1.2），一种半胱氨酸生物合成酶，在细胞提取物中会被叠氮钠抑制。分离出了能够在有抑制剂且无胱氨酸的情况下生长的AziB突变体。其中约一半定位于cysK基因，其产物O-乙酰丝氨酸巯基酶A [O-乙酰-L-丝氨酸乙酸裂解酶（加硫化氢）；EC 4.2.99.8]只有残余活性。野生型和aziA突变体对叠氮化物的敏感性也可被半胱氨酸生物合成的调节基因cysB中的组成型突变逆转。CysK和cysB突变体对叠氮化物和1,2,4-三唑表现出交叉抗性。提示这些突变体对叠氮化物的抗性是由于NADPH-亚硫酸盐还原酶活性增加所致。
