Search

The F1 complex of the ATP synthase of Streptomyces lividans was isolated and purified. The procedure involved the solubilization of F1 from membranes with buffer of low ionic strength in the presence of EDTA, ion-exchange chromatography and gel filtration. The purified F1 complex from S. lividans (SLF1) consists of five subunits α, β, γ, δ and ε with molecular masses of 58000, 50000, 36000, 28000 and 13000, respectively and exhibits immunological cross-reactivity with the F1 portion purified from Escherichia coli (ECF1). The enzymatic properties of SLF1 were determined by the use of microtiter-plate-based assay and compared with data obtained for ECF1. ATPase activity of SLF1 (specific activity: 20–30 U/mg) was only observed in the presence of high concentrations of Ca2+ (to mM). Stimulation of the ATPase activity by Mg2+ was not detectable; quite to the contrary, Mg2+ inhibited the Ca2+-stimulated activity of SLF1. SLF1 was re-bound to F1-stripped membranes of S. lividans, but not to F1-stripped membrane vesicles of E. coli. In contrast, ECF1 could be cross-reconstituted with F1-stripped membranes of S. lividans; however, a structural but not a functional reconstitution of the hybrid F1Fo complex was observed. [ABSTRACT FROM AUTHOR]

32P-labelled N-formyl methionyl transfer RNA from Escherichia coli strain CA265 was purified by chromatography on a column DEAE Sephadex followed by chromatography on benzoylated DEAE cellulose. Nucleotides from ribonuclease T1 and pancreatic ribonuclease digests of tRNAF were separated and their sequences determined. tRNAF consists of 77 nucleotides of which pCG is 5′-terminal and CAACCOH is 3′-terminal. [ABSTRACT FROM AUTHOR]