02646nas a2200217   4500008004100000022001400041245010800055210006900163260010300232300001400335490000700349520178900356653001002145653003602155653002402191653002802215653001902243100001902262700001802281856012902299       2013                        eng d  a0300-908400aEffect of different arginine methylations on the thermodynamics of tat peptide binding to HIV-1 TAR RNA0 aEffect of different arginine methylations on the thermodynamics   a23 RUE LINOIS, 75724 PARIS, FRANCEbELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIERcJUL  a1422-14310 v953 a<p>RNA-binding proteins are an important class of mediators that regulate cell function and differentiation. Methylation of arginine, a post-translational modification (PTM) found in these proteins, can modulate their function. Arginine can be monomethylated or dimethylated, depending on the type of methyl transferases involved. This paper describes a comparative study of the thermodynamics of unmodified and modified Tat peptide interaction with TAR RNA, where the peptide is methylated at epsilon (epsilon) and eta (eta) nitrogen atoms of guanidinium group of arginine side chain at position 52 or 53. The results indicate that monomethylation of arginine at epsilon (epsilon) nitrogen atom enhances binding affinity, owing to a more favourable enthalpy component which overrides the less favourable entropy change. In contrast, monomethylation of arginine residue at eta nitrogen results in reduced binding affinity originating exclusively from a less favourable enthalpy change leaving entropic component unaffected. However, in case of simultaneous methylation at epsilon and eta positions, the binding parameters remain almost unaffected, when compared to the unmodified peptide. In case of symmetric dimethylation at eta position the observed enthalpy change of the binding was found to be smaller than the values obtained for the unmodified peptide. Asymmetric dimethylation at eta position showed the most reduced binding affinities owing to less favourable enthalpy changes. These results provide insights that enable elucidation of the biological outcome of arginine methylation as PTMs that regulate protein function, and will contribute to our understanding of how these PTMs are established in vitro and in vivo. (C) 2013 Elsevier Masson SAS. All rights reserved.</p>10aHIV-110aPost-translational modification10aProtein methylation10aRNA-protein interaction10aThermodynamics1 aKumar, Santosh1 aMaiti, Souvik  uhttps://library.ncl.res.in/content/effect-different-arginine-methylations-thermodynamics-tat-peptide-binding-hiv-1-tar-rna-0