02740nas a2200217   4500008004100000022001400041245015100055210006900206260007100275300001400346490000800360520189600368100001802264700001602282700001402298700001602312700002202328700002602350700001802376856012802394       2009                        eng d  a1520-610600aEffects for the incorporation of five-atom thioacetamido nucleic acid (TANA) backbone on hybridization thermodynamics and kinetics of DNA duplexes0 aEffects for the incorporation of fiveatom thioacetamido nucleic   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a2944-29510 v1133 a<p>Thermodynamic studies of nucleic acids serve not only to widen our understanding on the nature and strength of forces that stabilize nucleic acids in a myriad of structural states they assume but also to facilitate the development of databases that could be used to predict the stability and selectivity of probe/primer-sets required in a broad range of nucleic acid-based diagnostic and therapeutic protocols. In the current study, we investigated the effect of a novel, backbone-modified ``thioacetamido linkage'' (TANA) on thermodynamics of hybridization, binding kinetics, and conformation of a DNA duplex. The modification comprises of an extended five-atom amide (N3'-CO-CH(2)-S-CH(2)) linker, as opposed to four-atom phosphodiester linker backbone present in DNA. One to three TANA-substitutions have been introduced in the linker backbone of two thymidine residues of one of the strand of the DNA duplex. Using spectroscopic and calorimetric techniques, we observed that TANA destabilizes the DNA helix by lowering the favorable enthalpy parameter of duplex formation. TANA center dot DNA duplexes were found to adopt a conformation toward an A-type duplex as shown by circular dichroism spectroscopy studies. Analysis of differential scanning calorimetry data indicated a nonzero heat capacity change, Delta C(p), accompanying the duplex formation. The average Delta C(p) change per duplex was found to be 832.5 cal mol(-1) K(-1), giving an average base-pair change of 59.5 cal (mol of base pairs)(-1) K(-1). Hybridization kinetic measurements using surface plasmon resonance indicated a decrease in binding affinity parameter (K(A)) that originates from higher dissociation rate constants (k(d)). Furthermore, optical melting studies showed that increasing the number of modifications results in a modest change in the number of counterions taken up during duplex formation.</p>1 aKaur, Harleen1 aArora, Amit1 aGogoi, K.1 aSolanke, P.1 aGunjal, Anita, D.1 aKumar, Vaijayanti, A.1 aMaiti, Souvik  uhttps://library.ncl.res.in/content/effects-incorporation-five-atom-thioacetamido-nucleic-acid-tana-backbone-hybridization-002572nas a2200205   4500008004100000022001400041245014700055210006900202260008000271300001200351490000800363520174800371100002502119700002302144700002002167700001802187700002102205700001602226856012402242       2012                        eng d  a0032-088900aMYB8 Controls inducible phenolamide levels by activating three novel hydroxycinnamoyl-coenzyme a:polyamine transferases in nicotiana attenuata0 aMYB8 Controls inducible phenolamide levels by activating three n  a15501 MONONA DRIVE, ROCKVILLE, MD 20855 USAbAMER SOC PLANT BIOLOGISTScJAN  a389-4070 v1583 a<p>A large number of plants accumulate N-acylated polyamines (phenolamides [PAs]) in response to biotic and/or abiotic stress conditions. In the native tobacco (Nicotiana attenuata), the accumulation of two major PAs, caffeoylputrescine and dicaffeoylspermidine (DCS), after herbivore attack is known to be controlled by a key transcription factor, MYB8. Using a broadly targeted metabolomics approach, we show that a much larger spectrum of PAs composed of hydroxycinnamic acids and two polyamines, putrescine and spermidine, is regulated by this transcription factor. We cloned several novel MYB8-regulated genes, annotated as putative acyltransferases, and analyzed their function. One of the novel acyltransferases (AT1) is shown to encode a hydroxycinnamoyl-coenzyme A: putrescine acyltransferase responsible for caffeoylputrescine biosynthesis in tobacco. Another gene (acyltransferase DH29), specific for spermidine conjugation, mediates the initial acylation step in DCS formation. Although this enzyme was not able to perform the second acylation toward DCS biosynthesis, another acyltransferase gene, CV86, proposed to act on monoacylated spermidines, was isolated and partially characterized. The activation of MYB8 in response to herbivore attack and associated signals required the activity of LIPOXYGENASE3, a gene involved in jasmonic acid (JA) biosynthesis in N. attenuata. These new results allow us to reconstruct a complete branch in JA signaling that defends N. attenuata plants against herbivores: JA via MYB8's transcriptional control of AT1 and DH29 genes controls the entire branch of PA biosynthesis, which allows N. attenuata to mount a chemically diverse (and likely efficient) defense shield against herbivores.</p>1 aOnkokesung, Nawaporn1 aGaquerel, Emmanuel1 aKotkar, Hemlata1 aKaur, Harleen1 aBaldwin, Ian, T.1 aGalis, Ivan  uhttps://library.ncl.res.in/content/myb8-controls-inducible-phenolamide-levels-activating-three-novel-hydroxycinnamoyl-0