Biogenic polyamines spermine and spermidine activate RNA polymerase and inhibit RNA helicase of hepatitis C virus.

Influence of the biogenic polyamines spermine, spermidine, and putrescine as well as their derivatives on the replication enzymes of hepatitis C virus (HCV) was investigated. It was found that spermine and spermidine activate HCV RNA-dependent RNA polymerase (NS5B protein). This effect was not caused by the stabilization of the enzyme or by competition with template-primer complex, but rather it was due to achievement of true maximum velocity V(max). Natural polyamines and their derivatives effectively inhibited the helicase reaction catalyzed by another enzyme of HCV replication - helicase/NTPase (NS3 protein). However, these compounds affected neither the NTPase reaction nor its activation by polynucleotides. Activation of the HCV RNA polymerase and inhibition of the viral helicase were shown at physiological concentrations of the polyamines. These data suggest that biogenic polyamines may cause differently directed effects on the replication of the HCV genome in an infected cell.

[Novel metabolically stable functionally-active mimetic of spermidine].

Earlier unknown 1,8-diamino-3-methyl-4-azaoctane (gamma-MeSpd) was synthesized. The analogue was not a substrate of ether spermine/spermidine N1-acetyltransferase, or spermine synthase, but was capable to support the growth of DU145 cells with depleted polyamine pool. Such a combination of y-MeSpd properties discloses novel opportunities to study cellular functions of catabolically unstable and easily interconvertible spermine and spermidine.

[Methylated analogues of spermine and spermidine as tools to investigate cellular functions of polyamines and the enzymes of their metabolism].

Biogenic amines spermine and spermidine are essential factors of cellular growth. Polyamine analogues are widely used to investigate and to regulate the enzymes of polyamine metabolism and functions of spermine and spermidine in vitro and in vivo. Recently, it was demonstrated that alpha-methylated derivatives of spermine and spermidine are capable to fulfill key cellular functions of polyamines, moreover in some cases of (R)- and (S)-isomers are actually different. Using these alpha-methylated spermine and spermidine analogues it turned possible to prevent the development of acute pancreatitis of SSAT-transgenic rats and to demostrate for the first time that polyamine oxidase, spermine oxidase and deoxyhypusine synthase have dormant stereospecificity. An original approach to regulate the stereospecificity of polyamine oxidase was suggested. It was also demonstrated that the depletion of the intracellular polyamine pool has both hypusine-related consequences and also the consequences unrelated to the posttranslational modification of eukaryotic initiation translation factor eIF5A. Possible applications of a new family of C-methylated polyamine analogues for the investigation and regulation of polyamine metabolism in vitro and in vivo are discussed.

Inhibition of agmatine transport in liver mitochondria by new charge-deficient agmatine analogues.

The charge of the agmatine analogues AO-Agm [N-(3-aminooxypropyl)guanidine], GAPA [N-(3-aminopropoxy)guanidine] and NGPG [N-(3-guanidinopropoxy)guanidine] is deficient as compared with that of agmatine and they are thus able to inhibit agmatine transport in liver mitochondria. The presence of the guanidine group is essential for an optimal effect, since AO-Agm and NGPG display competitive inhibition, whereas that of GAPA is non-competitive. NGPG is the most effective inhibitor (K(i)=0.86 mM). The sequence in the inhibitory efficacy is not directly dependent on the degree of protonation of the molecules; in fact NGPG has almost the same charge as GAPA. When the importance of the guanidine group for agmatine uptake is taken into account, this observation suggests that the agmatine transporter is a single-binding, centre-gated pore rather than a channel.

[Aminooxy analogues of spermine and their monoacetyl derivatives].

Convenient methods of synthesis of 1-aminooxy-3,8-diaza-11-aminoundecane, its earlier unknown N1-and N1 -acetyl derivatives, and also 1,10-bis(aminooxy)-3,8-diazadecane are suggested. It is shown a possibility to selectively delete the acid-labile ethoxyethylidene protection of aminooxy group by hydrosulfates in the presence of N-tert-butyloxycarbonyl group.

[Synthesis and antiviral activity of new 5-substituted 2'-deoxyuridine derivatives].

New 5-azole- and 5-oxime-substituted analogues of 2'-deoxyuridine are synthesized. The analogues with azole ring manifest low toxicities and antiherpetic activities on Vero cell culture, the imidazole derivative being the most active. The inhibitory effects of oximes of 5-formyl-deoxyuridine are comparable with those of the azole-containing nucleoside analogues, although their cytotoxicities are found to be higher; oxime of 5-formyldeoxyuridine is particularly toxic. The nucleoside analogues synthesized exhibit no marked activity on cell cultures infected with various variants of poxvirus. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 6; see also http://www.maik.ru.

[New charge-deficient agmatine analogs].

N,N'-Di-Boc-N"-triflylguanidine was demonstrated to be an efficient guanidinylation reagent for O-substituted hydroxylamines. N-(3-Aminooxypropyl)- and N-(3-aminopropoxy)guanidines, previously unknown isosteric and charge-deficient agmatine analogues, have been synthesized. The possibilities of using these compounds in studying polyamine metabolism are discussed. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 6; see also http://www.maik.ru.

[New oxaanalogues of spermine].

A new isosteric charge-deficient spermine analogue, 1,12-diamino-4,9-diaza-5-oxadodecan, and O-(7-amino-4-azaheptyl)oxime of 3-aminopropanal, a stable analogue of the Schiff base intermediate in the enzymatic oxidation of spermine, were synthesized. The possible use of these compounds for the inhibition of spermine oxidase is discussed.