Spermidine Analogues Research Articles

Plasma polyamines determined by negative-ion chemical ionization/mass spectrometry.

We have developed an accurate and highly sensitive gas-chromatographic/mass-spectrometric procedure for determining di- and polyamines (putrescine, spermidine, and spermine) in plasma and erythrocytes. Deuterium-labeled analogs of putrescine, spermidine, and spermine were synthesized for use as internal standards. Trifluoroacetyl derivatives of the polyamines were formed during the procedure and then detected with negative-ion chemical ionization/mass spectrometry in combination with multiple ion monitoring. Limits of sensitivity ranged from 0.25 to 1.0 pmol of analyte injected into the instrument.

DNA condensation with polyamines: I. Spectroscopic studies

The addition of polyamines with three or four positive charges to very dilute solutions of phage T7 DNA leads to a co-operative condensation. The reaction is very rapid and the DNA remains in the B-form as characterized by circular dichroism. The particles which are formed are roughly the size of a phage particle when they are prepared for electron microscopy. This aspect is discussed more completely in the accompanying paper (Chattoraj et al., 1978). Most of the experiments were performed at low ionic strength (roughly 0.002 m) with the triamine, spermidine. The reaction also occurs in 0.15 m-sodium chloride but here the experiments are accompanied by slow irreversible effects which are evidently due to aggregation since they are accompanied by a commensurate increase in turbidity. Consequently, most of the experiments have been done under the reversible low ionic strength conditions. Neither Mg 2+ nor the diamine putrescine produce the reaction at concentrations similar to those found in bacterial cells. The tetramer spermine, on the other hand, which is not found in bacterial cells, is a very strong condensation agent in the μ m region. The spermidine analog, bis-(3-aminopropyl)amine is very similar in behavior to spermidine. The role which polyamines might play in the condensation of DNA in phage heads is discussed.

Polyamines in the synthesis of bacteriophage deoxyribonucleic acid. II. Requirement for polyamines in T4 infection of a polyamine auxotroph.

Polyamine depletion produced by exogenous arginine in Escherichia coliK-12 cultures defective in agmatine ureohydrolase activity resulted in a marked inhibition of the rates of growth and nucleic acid synthesis. Addition of putrescine or spermidine to such depleted cultures restored the control rate of growth and nucleic acid accumulation. The omission of lysine resulted in a further decrease in the rates of growth and nucleic acid synthesis in polyamine-depleted cells. The addition of exogenous cadaverine increased the rates of growth and ribonucleic acid synthesis to those observed in lysine-supplemented cultures, suggesting that lysine or a derivative of lysine serves a function similar to cadaverine. Addition of lysine to polyamine-depleted cultures at neutral pH results in the synthesis of cadaverine and a new spermidine analogue, both containing lysine carbon. This new metabolite has been isolated and identified as N-3-aminopropyl-1, 5-diaminopentane. T4D infection of the polyamine-depleted mutant resulted in a very low rate of DNA synthesis and phage maturation. The addition of putrescine or spermidine 15 min before infection restored phage DNA synthesis and phage maturation to control rates, i.e., rates observed in infected cells grown in the absence of arginine.

Polyamine stimulation of nucleic acid synthesis in an uninfected and phage-infected polyamine auxotroph of Escherichia coli K12 (arginine-agmatine ureohydrolase-putrescine-spermidine-lysine-cadaverine).

The addition of arginine to cultures of Escherichia coli K12 deficient in agmatine ureohydrolase (EC 3.5.3.7) results in polyamine depletion and a striking inhibition of nucleic acid accumulation and growth. The omission of lysine from these cultures leads to a further decrease in growth rate and nucleic acid synthesis. In arginine-inhibited cells the addition of putrescine or spermidine, in the presence or absence of lysine, restores the control rate of growth and nucleic acid accumulation. Under the same conditions of arginine inhibition in the absence of lysine, the addition of cadeverine alone stimulates growth rate and RNA synthesis. The addition of lysine to polyamine-depleted cultures results in cadaverine production and in the appearance of a new spermidine analogue, containing lysine carbon. The new compound has been identified as N-3-aminopropyl-1,5-diaminopentane. Infection of this arginine-inhibited, polyamine-depleted mutant with T(4)D results in markedly decreased amounts of DNA accumulation, as compared to infected cells uninhibited by arginine. Supplementation of arginine-inhibited infected cells by putrescine or spermidine restores DNA synthesis to the uninhibited level.

The effect of polyamines on the methylation of Escherichia coli methyl-deficient transfer RNA by their homologous methylases

The polyamines, putrescine, spermidine, and spermine, in low concentration stimulate the rate of in vitro homologous Escherichia coli tRNA methylation. Under optimal conditions polyamines cause a greater stimulation of the rate of methylation than Mg 2+. However, the presence of polyamines does not cause any significant hypermethylation of a fully-methylated homologous substrate. The polyamine stimulatory effect is not attributable to the protection of any of the labile components in the methylation reaction mixture. Analogs of putrescine and spermidine, differing only in the hydrocarbon chain length separating the positively charged ammonium groups, also cause quantitatively comparable stimulation. The positively charged ammonium groups of the polyamines are essential for stimulation since affixing a methyl group to a terminal nitrogen lowers the amount of stimulation and their replacement by alcoholic functional groups completely abolishes stimulation. These polyamines cause a shift in the melting curves of tRNA. The monovalent cations, NH +, Na +, K +, and Li + in moderate concentrations also stimulate the rate of tRNA methylation. Anions, on the other hand, are inhibitory. Electrophoresis and chromatography of [ Me- 14C]nucleotides produced by the alkaline hydrolysis of the 14CH 3-labeled tRNA products demonstrate that while the percentage distribution of radioactivity among the methylated nucleotides are grossly similar for tRNA methylation governed by Mg 2+, polyamines, or NH 4 +, the relative abundance of 7-methylguanylic acid increases for putrescine, spermidine, and NH 4 + stimulated methylation. Polyamines and Mg 2+ show a competitive, mutual antagonism. Increasing the Mg 2+ concentration reduces the polyamine stimulation immediately and precipitously. On the other hand, monovalent cations are not antagonistic towards either Mg 2+ or polyamines. Increasing Mg 2+ does not precipitously lower monovalent cation stimulation. The results presented can be explained by postulating that Mg 2+ and polyamines bind to tRNA inducing configurational changes favorable for methylation, whereas monovalent cations are not specific site binding, but milieu-altering agents.

ANALOGS OF SPERMINE AND SPERMIDINE. I. SYNTHESIS OF POLYMETHYLENEPOLYAMINES BY REDUCTION OF CYANOETHYLATED ALPHA,OMEGA-ALKYLENEDIAMINES.

ANALOGS OF SPERMINE AND SPERMIDINE. I. SYNTHESIS OF POLYMETHYLENEPOLYAMINES BY REDUCTION OF CYANOETHYLATED ALPHA,OMEGA-ALKYLENEDIAMINES.