Publications

• Properties of putrescine uptake by PotFGHI and PuuP and their physiological significance in Escherichia coli.

  Terui Y., Saroj S.D., Sakamoto A., Yoshida T., Higashi K., Kurihara S., Suzuki H., Toida T., Kashiwagi K., Igarashi K.

  Properties of putrescine uptake by PotFGHI and PuuP and their physiological significance were studied using a polyamine biosynthesis and uptake deficient Escherichia coli KK3131 transformed with pACYC184 containing potFGHI or puuP. Putrescine uptake activity of E. coli KK3131 transformed with pACY ... >> More

  Properties of putrescine uptake by PotFGHI and PuuP and their physiological significance were studied using a polyamine biosynthesis and uptake deficient Escherichia coli KK3131 transformed with pACYC184 containing potFGHI or puuP. Putrescine uptake activity of E. coli KK3131 transformed with pACYC184-PotFGHI was higher than that of E. coli 3131 transformed with pACYC-PuuP when cells were cultured in the absence of putrescine. Putrescine uptake by PotFGHI was both ATP and membrane potential dependent, while that by PuuP was membrane potential dependent. Feedback inhibition by polyamines occurred at the PotFGHI uptake system but not at the PuuP uptake system. Expression of PuuP was reduced in the presence of PuuR, a negative regulator for PuuP, and expression of PuuR was positively regulated by glucose, which reduces the level of cAMP. The complex of cAMP and CRP (cAMP receptor protein) inhibited the expression of PuuR in the absence of glucose. Thus, the growth rate of E. coli KK3131 in the presence of both 0.4% (22.2 mM) glucose and 10 mM putrescine was in the order of cells transformed with pACYC-PotFGHI > pACYC-PuuP > pACYC-PuuP + PuuR, which was parallel with the polyamine content in cells. The results indicate that PotFGHI is necessary for rapid cell growth in the presence of glucose as an energy source. When glucose in medium was depleted, however, PuuP was absolutely necessary for cell growth in the presence of putrescine, because accumulation of putrescine to a high level by PuuP was necessary for utilization of putrescine as an energy source. << Less

  Amino Acids 46:661-670(2014) [PubMed] [EuropePMC]

• Characteristics of the operon for a putrescine transport system that maps at 19 minutes on the Escherichia coli chromosome.

  Pistocchi R., Kashiwagi K., Miyamoto S., Nukui E., Sadakata Y., Kobayashi H., Igarashi K.

  The nucleotide sequence of the operon for the putrescine transport system that maps at 19 min on the Escherichia coli chromosome was determined. It contained four open reading frames encoding potF, -G, -H, and -I proteins. The potF protein (M(r) = 38,000) was inferred to be a putrescine-specific b ... >> More

  The nucleotide sequence of the operon for the putrescine transport system that maps at 19 min on the Escherichia coli chromosome was determined. It contained four open reading frames encoding potF, -G, -H, and -I proteins. The potF protein (M(r) = 38,000) was inferred to be a putrescine-specific binding protein existing in a periplasmic fraction from the results of Western blot analysis of the cell fractions and from measurements of polyamine binding to the protein. The potG protein (M(r) = 45,000) had consensus amino acid sequences for the nucleotide-binding site. The potH (M(r) = 35,000) and potI (M(r) = 31,000) proteins consisted of six putative transmembrane-spanning segments linked by hydrophilic segments of variable length as shown by hydropathy profiles. The spermidine-putrescine transport system, which is mainly involved in spermidine transport, consisted of potA, -B, -C, and -D proteins (Furuchi, T., Kashiwagi, K., Kobayashi, H., and Igarashi, K. (1991) J. Biol. Chem. 266, 20928-20933). The homologies of the corresponding two proteins between those two systems, F and D, G and A, H and B, and I and C, were 35, 42, 37, and 36%, respectively. The initiation point of the transcription of the operon for the putrescine transport system was determined by primer extension and S1 nuclease mapping. Transcription started from the T residue located either 149 or 150 nucleotides upstream from the initiator AUG codon of potF protein mRNA. By making several subclones and a mutant lacking the potF gene, we showed that the expression of all four proteins was necessary for maximal putrescine transport activity. These results indicate that the putrescine transport system can also be defined as a bacterial periplasmic transport system. << Less

  J. Biol. Chem. 268:146-152(1993) [PubMed] [EuropePMC]