Valdivia R H, Wang L, Winans S C
Section of Microbiology, Cornell University, Ithaca, New York 14853.
J Bacteriol. 1991 Oct;173(20):6398-405. doi: 10.1128/jb.173.20.6398-6405.1991.
Neoplastic crown gall tumors incited by Agrobacterium tumefaciens release novel amino acid or sugar derivatives known as opines, whose synthesis is directed by genes transferred to plant cells. Agrobacterium cells can transport and catabolize these compounds as sources of carbon and nitrogen. This article describes a region of the pTiA6 plasmid which is required for catabolism of the opine octopine and whose transcription is induced by octopine. This region of the plasmid contains four open reading frames, occQ, occM, occP, and occJ, which show homology to the family of so-called shock-sensitive permeases. TnphoA mutagenesis demonstrated that the OccJ and OccM proteins lie fully or partly in the periplasmic space. The OccJ protein was identified by electrophoresis and found to be fully localized in the periplasmic space. When these proteins were expressed in Escherichia coli, radiolabeled octopine became cell-associated.
由根癌土壤杆菌引发的肿瘤性冠瘿瘤会释放出名为冠瘿碱的新型氨基酸或糖衍生物，其合成由转移至植物细胞的基因指导。土壤杆菌细胞能够将这些化合物作为碳源和氮源进行运输及分解代谢。本文描述了pTiA6质粒上一个区域，该区域对于冠瘿碱章鱼碱的分解代谢是必需的，并且其转录由章鱼碱诱导。质粒的这个区域包含四个开放阅读框，即occQ、occM、occP和occJ，它们与所谓的休克敏感通透酶家族具有同源性。TnphoA诱变表明，OccJ和OccM蛋白完全或部分位于周质空间。通过电泳鉴定出OccJ蛋白，发现其完全定位于周质空间。当这些蛋白在大肠杆菌中表达时，放射性标记的章鱼碱与细胞相关联。
