Amino acid-dependent control of the transport of α-methyl glucoside in [formula omitted

Abstract

RNA synthesis in E. coli is dependent on the presence of a full complement of amino acids and the locus “RC” on its chromosome is responsible for the control of RNA synthesis ( Borek, Ryan and Rockenbach, 1955; Pardee and Prestidge, 1956; Stent and Brenner, 1961). However, we have recently demonstrated that the incorporation of 14C-acetate into lipid fraction is subject to amino acid control in stringent strains of E. coli (Sokawa, Nakao and Kaziro, 1968). Moreover, the synthesis of carbohydrate was shown to be also dependent on the presence of amino acids (Sokawa, Nakao and Kaziro, unpublished). Consequently, it was suggested that the control by RC gene is not limited to RNA synthesis, and many other biosynthetic reactions might be regulated by RC gene. In this paper we wish to report our recent observation that the transport of α-methyl D-glucoside (α-MG), a non-metabolizable analog of glucose permeation system (Kepes and Cohen, 1962), is also under amino acid control in E. coli . The stringent strains fail to accumulate 14C-α-MG during amino acid starvation whereas the relaxed strains continue to uptake 14C-α-MG in the absence of required amino acids. As in the case of RNA and lipid synthesis, addition of chloramphenicol (CM) restores the transport of α-MG under conditions of amino acid starvation in stringent strains.