Amplification of the put genes and identification of the put gene products in Escherichia coli K12

1980 ◽  
Vol 58 (10) ◽  
pp. 787-796 ◽  
Author(s):  
Janet M. Wood ◽  
David Zadworny

The utilization of L-proline as carbon or nitrogen source for the growth of Escherichia coli K12 requires the activities of an L-proline porter (PP-I) and a bifunctional L-proline dehydrogenase – Δ1-pyrroline carboxylate dehydrogenase. PP-I is inactivated by mutations at putP and the bifunctional dehydrogenase is encoded in the adjacent locus, putA, at 22 min on the chromosome map. Two additional loci, proP (at 92 min) and proT (at 82 min), have also been implicated in L-proline transport. We have studied four ColE1/E. coli K12 hybrid plasmids from the plasmid bank prepared by Clarke and Carbon. Each of these plasmids was shown previously to complement an L-proline transport defect in E. coli. Genetic complementation analysis and biochemical assays of L-proline transport and L-proline dehydrogenase activity show that three of these hybrid plasmids bear the putPA region of the E. coli chromosome (plasmids pLC4-45, pLC10-29, and pLC43-41). The fourth plasmid, pLC35-38, specifically enhances the L-proline transport activity of its host bacteria but not their L-proline dehydrogenase activity. It probably encodes putP. We have used these plasmids in an E. coli minicell system to identify the putA and putP gene products.

Genetics ◽  
1987 ◽  
Vol 115 (3) ◽  
pp. 419-429
Author(s):  
Maja Kricker ◽  
Barry G Hall

ABSTRACT The cellobiose catabolic system of Escherichia coli K12 is being used to study the role of cryptic genes in microbial evolution. Wild-type E. coli K12 do not utilize the β-glucoside sugars, arbutin, salicin and cellobiose. A Cel+ (cellobiose utilizing) mutant which grows on cellobiose, arbutin, and salicin was isolated previously from wild-type E. coli K12. Biochemical assays indicate that a cel structural gene (celT) specifies a single transport protein that is a β-glucoside specific enzyme of the phosphoenolpyruvate-dependent phosphotransferase system. The transport protein phosphorylates β-glucosides at the expense of phosphoenolpyruvate. A single phosphoglucosidase, specified by celH, hydrolyzes phosphorylated cellobiose, arbutin, and salicin. The genes of the cel system are expressed constitutively in the Cel+ mutant, whereas they are not expressed at a detectable level in the wild-type strain. The transport and hydrolase genes are simultaneously silenced or simultaneously expressed and thus constitute an operon. Cel+ strains which fail to utilize one or more β-glucosides express the transport system at a lower level than do Cel+ strains which grow on all three β-glucosides. Other strains inducibly express a gene which specifies transport of arbutin but not the other β-glucosides. The arbutin transport gene, arbT, maps outside of the cel locus.


1985 ◽  
Vol 5 (10) ◽  
pp. 2653-2661 ◽  
Author(s):  
B Ferguson ◽  
B Krippl ◽  
O Andrisani ◽  
N Jones ◽  
H Westphal ◽  
...  

We previously purified and characterized functionally the Escherichia coli-expressed product of the human subgroup C adenovirus E1A 13S mRNA (B. Ferguson, N. Jones, J. Richter, and M. Rosenberg, Science 224:1343-1346, 1984; B. Krippl, B. Ferguson, M. Rosenberg, and H. Westphal, Proc. Natl. Acad. Sci. USA 81:6988-6992, 1984). We have now expressed in E. coli and purified the protein product encoded by the human subgroup C adenovirus E1A 12S mRNA and have compared the functional properties of this protein with those of the E1A 13S mRNA product. Using microinjection techniques to introduce these proteins into mammalian cells, we found that the E1A 12S mRNA product, like the 13S mRNA product, localized rapidly to the cell nucleus and induced adenovirus gene expression. Although both E1A gene products localized to the nucleus and stimulated adenovirus gene transcription, these proteins did not directly bind to DNA under conditions in which a known DNA-binding protein, the human c-myc gene product, bound DNA efficiently. Thus, the E1A and myc gene products, which have been related both structurally and functionally, exhibit distinctly different biochemical properties.


2007 ◽  
Vol 189 (11) ◽  
pp. 4325-4327 ◽  
Author(s):  
Sarah E. Broadbent ◽  
Roberto Balbontin ◽  
Josep Casadesus ◽  
Martin G. Marinus ◽  
Marjan van der Woude

ABSTRACT The Caulobacter crescentus DNA adenine methyltransferase CcrM and its homologs in the α-Proteobacteria are essential for viability. CcrM is 34% identical to the yhdJ gene products of Escherichia coli and Salmonella enterica. This study provides evidence that the E. coli yhdJ gene encodes a DNA adenine methyltransferase. In contrast to an earlier report, however, we show that yhdJ is not an essential gene in either E. coli or S. enterica.


1977 ◽  
Vol 162 (2) ◽  
pp. 309-320 ◽  
Author(s):  
P J F Henderson ◽  
R A Giddens ◽  
M C Jones-Mortimer

1. Strains of Escherichia coli K12 were made that are unable to assimilate glucose by the phosphotransferase system, since they lack the glucose-specific components specified by the genes ptsG and ptsM. 2. Derivative organisms lacking the methyl galactoside or galactose-specific transport system were examined for their ability to transport galactose, d-fucose, methyl beta-D-galactoside, glucose, 2-deoxy-D-glucose and methyl alpha-D-glucoside. 3. Galactose, glucose and to a lesser extent fucose are substrates for both transport systems. 4. 2-Deoxyglucose is transported on the galactose-specific but not the methyl galactoside system. 5. The ability of sugars to elicit anaerobic proton transport is associated with the galactose-specific, but not with the methyl galactoside transport activity. Hence a chemiosmotic mechanism of energization is likely to apply to the former but not to the latter. Alternatively the methyl galactoside system may be switched off under certain conditions, which would indicate a novel regulatory mechanism. 6. Details of the procedure for the derivation of strains may be obtained from the authors, and have been deposited as Supplementary Publication SUP 50074 (8 pages at the) British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977), 161,1.


1971 ◽  
Vol 124 (5) ◽  
pp. 905-913 ◽  
Author(s):  
R. V. Krishna ◽  
P. R. Krishnaswamy ◽  
D. Rajagopal Rao

1. Cell-free extracts of Escherichia coli K12 catalyse the synthesis of N-acetyl-l-phenylalanine from acetyl-CoA and l-phenylalanine. 2. The acetyl-CoA–l-phenylalanine α-N-acetyltransferase was purified 160-fold from cell-free extracts. 3. The enzyme has a pH optimum of 8 and catalyses the acetylation of l-phenylalanine. Other l-amino acids such as histidine and alanine are acetylated at slower rates. 4. A transacylase was also purified from E. coli extracts and its substrate specificity studied. 5. The properties of both these enzymes were compared with those of other known amino acid acetyltransferases and transacylases.


1982 ◽  
Vol 28 (4) ◽  
pp. 425-430 ◽  
Author(s):  
Hiroaki Nakayama ◽  
Koji Nakayama ◽  
Ritsuko Nakayama ◽  
Yasuko Nakayama

In an approach to characterizing the nature of the lethal event in thymineless death (TLD), rec mutants of Escherichia coli K12 were examined for their sensitivity to TLD. The recB21 and recC22 mutations sensitized cells of the AB1157 line to TLD but not cells of the HF4733 line. This increased sensitivity was not suppressed substantially by either sbcB15 or xonA1 mutation. In contrast, a recF mutation appeared to make cells more resistant to TLD than rec+ cells. Three different recA alleles were shown not to affect TLD appreciably. These results not only provide further support for the view that the site of the lethal event in TLD is cellular DNA, but also strongly suggest the involvement of the recBC and recF gene products in TLD. The apparent indifference of recA mutation implies that the conventional recombination and repair pathways per se are not involved in TLD and that the hypothetical lethal damage to DNA may be unique in nature.


1998 ◽  
Vol 64 (2) ◽  
pp. 411-418 ◽  
Author(s):  
Katsuhisa Suzuki ◽  
Norio Wakao ◽  
Tetsuya Kimura ◽  
Kazuo Sakka ◽  
Kunio Ohmiya

ABSTRACT The arsenic resistance (ars) operon from plasmid pKW301 of Acidiphilium multivorum AIU 301 was cloned and sequenced. This DNA sequence contains five genes in the following order: arsR, arsD, arsA,arsB, arsC. The predicted amino acid sequences of all of the gene products are homologous to the amino acid sequences of the ars gene products of Escherichia coliplasmid R773 and IncN plasmid R46. The ars operon cloned from A. multivorum conferred resistance to arsenate and arsenite on E. coli. Expression of the arsgenes with the bacteriophage T7 RNA polymerase-promoter system allowedE. coli to overexpress ArsD, ArsA, and ArsC but not ArsR or ArsB. The apparent molecular weights of ArsD, ArsA, and ArsC were 13,000, 64,000, and 16,000, respectively. A primer extension analysis showed that the ars mRNA started at a position 19 nucleotides upstream from the arsR ATG in E. coli. Although the arsR gene of A. multivorum AIU 301 encodes a polypeptide of 84 amino acids that is smaller and less homologous than any of the other ArsR proteins, inactivation of the arsR gene resulted in constitutive expression of the ars genes, suggesting that ArsR of pKW301 controls the expression of this operon.


1985 ◽  
Vol 5 (10) ◽  
pp. 2653-2661
Author(s):  
B Ferguson ◽  
B Krippl ◽  
O Andrisani ◽  
N Jones ◽  
H Westphal ◽  
...  

We previously purified and characterized functionally the Escherichia coli-expressed product of the human subgroup C adenovirus E1A 13S mRNA (B. Ferguson, N. Jones, J. Richter, and M. Rosenberg, Science 224:1343-1346, 1984; B. Krippl, B. Ferguson, M. Rosenberg, and H. Westphal, Proc. Natl. Acad. Sci. USA 81:6988-6992, 1984). We have now expressed in E. coli and purified the protein product encoded by the human subgroup C adenovirus E1A 12S mRNA and have compared the functional properties of this protein with those of the E1A 13S mRNA product. Using microinjection techniques to introduce these proteins into mammalian cells, we found that the E1A 12S mRNA product, like the 13S mRNA product, localized rapidly to the cell nucleus and induced adenovirus gene expression. Although both E1A gene products localized to the nucleus and stimulated adenovirus gene transcription, these proteins did not directly bind to DNA under conditions in which a known DNA-binding protein, the human c-myc gene product, bound DNA efficiently. Thus, the E1A and myc gene products, which have been related both structurally and functionally, exhibit distinctly different biochemical properties.


Sign in / Sign up

Export Citation Format

Share Document