Kim Y S, Kim E J
Department of Biochemistry, College of Science, Yonsei University, Seoul, Korea.
Plasmid. 1994 Sep;32(2):219-21. doi: 10.1006/plas.1994.1058.
A novel, broad-host-range 60-kb R-plasmid, which encodes for malonate assimilation, was isolated from Pseudomonas fluorescens and was designated pPSF1. Pseudomonas, which can utilize malonate as a sole carbon source, was unable to grow on malonate medium upon curing with mitomycin C, indicating loss of plasmid pPSF1. Furthermore, Escherichia coli transformed with pPSF1 was able to grow on malonate medium as a sole carbon source. Malonate decarboxylase, a key enzyme in malonate assimilation, was detected in transformed E. coli grown on malonate. pPSF1 also encodes resistance to several antibiotics such as ampicillin, kanamycin, and streptomycin and is transmissible between E. coli and Pseudomonas by conjugation.
从荧光假单胞菌中分离出一种新型的、宿主范围广泛的60 kb R质粒，它编码丙二酸同化作用，被命名为pPSF1。能够利用丙二酸作为唯一碳源的假单胞菌，在用丝裂霉素C消除质粒后无法在丙二酸培养基上生长，这表明质粒pPSF1已丢失。此外，用pPSF1转化的大肠杆菌能够在以丙二酸为唯一碳源的培养基上生长。在以丙二酸为碳源生长的转化大肠杆菌中检测到了丙二酸脱羧酶，它是丙二酸同化作用中的关键酶。pPSF1还编码对几种抗生素的抗性，如氨苄青霉素、卡那霉素和链霉素，并且可以通过接合在大肠杆菌和假单胞菌之间进行转移。
