TY - JOUR
T1 - Isolation of a protein coded for by the permease gene of the Lac operon of Escherichia coli
AU - Kolber, Alan R.
AU - Stein, W. D.
PY - 1967/3
Y1 - 1967/3
N2 - We can only presume from the results of our investigations, that the peak area of14C enrichment having neither galactosidase nor triansacetylase activity, and which is not present in the chromatograph of the permease-less (200 P) mutant, must be the protein expression of the permease (y+) gene of E. coli. This protein is apparently cytoplasmic. There are, however, several alternatives to the hypothesis that this product is the membrane carrier itself. Indeed, if it is the carrier, we must explain why it appears only in the cytoplasm, and not in the membrane fraction. Had the permease been dislodged from the membrane during osmotic lysis and the subsequent buffer extraction, we should presumably have detected some residual14C enrichment in the membrane fractions. This we could not find. Moreover, accumulated evidence to date leads us to surmise that transport "carriers" are located in the cell membrane [4, 5, 6, 7]. What, then, is the protein coded for by the permease gene? There is the possibility that, as the galactoside transport system is an active, energy-requiring system, what we have separated is that portion of this system from which the active transport derives its energy. Alternatively, we may have located the protein (enzyme) system responsible for the synthesis of a non-protein carrier molecule. If the carrier is of a lipid or phospholipid nature (4, 6), the added14C and3H phenylalanine might not label the carrier itself but would be incorporated into an ancillary system such as that described above. All of these possibilities must certainly be explored, but it is at least evident that the techniques outlined in this report can be used successfully to isolate physically, and to characterize, cellular components linked to transport functions.
AB - We can only presume from the results of our investigations, that the peak area of14C enrichment having neither galactosidase nor triansacetylase activity, and which is not present in the chromatograph of the permease-less (200 P) mutant, must be the protein expression of the permease (y+) gene of E. coli. This protein is apparently cytoplasmic. There are, however, several alternatives to the hypothesis that this product is the membrane carrier itself. Indeed, if it is the carrier, we must explain why it appears only in the cytoplasm, and not in the membrane fraction. Had the permease been dislodged from the membrane during osmotic lysis and the subsequent buffer extraction, we should presumably have detected some residual14C enrichment in the membrane fractions. This we could not find. Moreover, accumulated evidence to date leads us to surmise that transport "carriers" are located in the cell membrane [4, 5, 6, 7]. What, then, is the protein coded for by the permease gene? There is the possibility that, as the galactoside transport system is an active, energy-requiring system, what we have separated is that portion of this system from which the active transport derives its energy. Alternatively, we may have located the protein (enzyme) system responsible for the synthesis of a non-protein carrier molecule. If the carrier is of a lipid or phospholipid nature (4, 6), the added14C and3H phenylalanine might not label the carrier itself but would be incorporated into an ancillary system such as that described above. All of these possibilities must certainly be explored, but it is at least evident that the techniques outlined in this report can be used successfully to isolate physically, and to characterize, cellular components linked to transport functions.
UR - http://www.scopus.com/inward/record.url?scp=0014043548&partnerID=8YFLogxK
U2 - 10.1007/BF01248050
DO - 10.1007/BF01248050
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 5341239
AN - SCOPUS:0014043548
SN - 0033-183X
VL - 63
SP - 309
EP - 314
JO - Protoplasma
JF - Protoplasma
IS - 1-3
ER -