Stimulation of arginine transport in osmotically shocked Escherichia coli W cells by purified arginine-binding protein fractions.

Content Provider	Semantic Scholar
Author	Wilson, Onslow H. Holden, Joseph T.
Copyright Year	1969
Abstract	Abstract Cold osmotic shock treatment of early stationary phase Escherichia coli W cells reduced the capacity for arginine uptake and accumulation by about 25%. DEAE-cellulose chromatography of the shock fluid separated four protein-containing fractions having relatively specific arginine-binding activity. The reduced transport activity of shocked cells was partially restored by two of these purified protein fractions (I and III). The degree of restoration was linear between 5 and 10 µg per ml for Fraction I; above 10 µg per ml there was a marked reduction in the extent of stimulation. For Fraction III restoration of the initial rate (15 sec) was a curvilinear function of the protein concentration from 5 to 40 µg per ml. The degree of restoration of the steady state level of uptake (5 min) hardly changed within this protein concentration range. Fractions I and III have identical dissociation constants for arginine, the values ranging from 0.5 to 1 x 10-6 m. 14C-Arginine was not metabolized by concentrated crude shock protein. The material bound by this protein solution and by purified Fractions I and III was found to have the same Rf value as free arginine. Analysis of the intracellular pool radioactivity after exposure of shocked cells to 14C-arginine and to 14C-arginine plus optimal concentrations of Fractions I and III (in the presence of 4 x 10-3 m amineoxyacetic acid) showed that the bulk of the radioactivity (∼90%) remained in arginine, thereby showing that these proteins stimulate the arginine accumulation process. The proteins are specific in binding and stimulating the transport of arginine. They bound little or no lysine and canavanine and did not stimulate the transport of lysine in shocked cells. These data suggest that cold osmotic shock treatment of E. coli W releases proteins which may participate in the accumulation of arginine by these cells, and that these proteins are not capable of functioning in the accumulation of lysine.
File Format	PDF HTM / HTML
PubMed reference number	4890231
Journal	Medline
Volume Number	244
Issue Number	10
Alternate Webpage(s)	http://www.jbc.org/content/244/10/2743.full.pdf
Journal	The Journal of biological chemistry
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article