Área de Microbiología, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain.
Microb Biotechnol. 2011 Mar;4(2):216-25. doi: 10.1111/j.1751-7915.2010.00222.x. Epub 2010 Nov 2.
A protein highly overrepresented in the proteome of Streptomyces clavuligerus oppA2::aph was characterized by MS/MS as a rhodanese-like enzyme. The rhlA gene, encoding this protein, was deleted from strains S. clavuligerus ATCC 27064 and S. clavuligerus oppA2::aph to characterized the RhlA enzyme activity, growth on different sulfur sources and antibiotic production by the mutants. Whereas total thiosulfate sulfurtransferase activity in cell extracts was not affected by the rhlA deletion, growth, cephamycin C and clavulanic acid production were impaired in the rhlA mutants. Holomycin production was drastically reduced (66-90%) in the rhlA mutants even when using S. clavuligerusΔrhlA pregrown cells, suggesting that this enzyme might be involved in the formation of the cysteine precursor for this sulfur-containing antibiotic. While growth on thiosulfate as the sole sulfur source was particularly low the volumetric and specific antibiotic production of the three antibiotics increased in all the strains in the presence of thiosulfate. This stimulatory effect of thiosulfate on antibiotic production was confirmed by addition of thiosulfate to pre-grown cells and appears to be a general effect of thiosulfate on oxidative stress as was also evident in the production of staurosporin by S. clavuligerus.
一种在链霉菌属克拉维酸产生菌的蛋白质组中高度过表达的蛋白，经 MS/MS 鉴定为类似于硫氰酸酶的酶。rhlA 基因，编码这种蛋白质，从链霉菌属克拉维酸产生菌 ATCC 27064 和链霉菌属克拉维酸 oppA2::aph 菌株中缺失，以表征 RhlA 酶活性、不同硫源上的生长和突变体抗生素的产生。尽管细胞提取物中的总硫代硫酸盐硫转移酶活性不受 rhlA 缺失的影响，但 rhlA 突变体的生长、头孢菌素 C 和克拉维酸的产生受到了损害。即使使用链霉菌属克拉维酸ΔrhlA 预培养细胞，霍洛霉素的产生也大大降低（66-90%），表明该酶可能参与了这种含硫抗生素的半胱氨酸前体的形成。虽然以硫代硫酸盐为唯一硫源的生长特别低，但在所有菌株中，在存在硫代硫酸盐的情况下，三种抗生素的体积和特定抗生素的产量都增加了。硫代硫酸盐对抗生素产生的这种刺激作用通过向预培养细胞中添加硫代硫酸盐得到了证实，并且似乎是硫代硫酸盐对氧化应激的普遍影响，这在链霉菌属产生的司他夫定中也很明显。
