甲基单胞菌甲烷单加氧酶缺陷突变株的研究

THE STUDY ON THE MUTANTS DEFECTIVE IN MMO ACTIVITY FROM A METHANOTROPH METHYLOMONAS SP.761M

用高剂量紫外线诱变Ⅰ型专性甲烷营养菌(Methylomonas sp.)761 AR 菌株,获得了9个甲烷单加氧酶缺陷突变株。对其中761AR-55突变株的进一步研究表明,此菌株完全丧失了氧化甲烷及氧化丙烯为环氧丙烷的能力,证明其甲烷单加氧酶活性存在缺陷。而其它特性如 DNA 内切酶谱,DNA 中 G+C 克分子含量,可溶性蛋白电泳谱带,以及细胞内膜结构均与亲本菌株一致。

The methanol-utilizing mutant 761AR ofa Type Ⅰ obligate methanotroph,Methylomo-has sp.761M,was mutagenized by using highdosage of ultraviolet irradiation.Nine mu-tant strains defective in MMO activity werescreened out by testisg their ability to grow onthe plates with methanol or methane as carbonsourse.Further studies on one of these mutan-ts,761AR-55,revealed that this strain had en-tirely lost the MMO activity by measuring bo-th the ability of methane oxidization and thatof oxidizing propene to epoxy propane.Inspite of the MMO defection,other character-istics of this mutant including the PstⅠ-diges-tion patterns and G+C% of chromosomalDNA,the SDS-PAGE patterns of soluble pro-ceihs,and the ultrastructure of intracytoplas-mic membranes,remained identical to the wildtype strain 761M.