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

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.

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-002245nas a2200253 4500008004100000022001400041245007200055210006900127260000800196300000800204490000800212520141600220653002001636653002001656653003601676653002301712653005101735100001901786700001801805700001701823700002601840700002801866856009701894 2020 eng d a0981-942800aStructure and regulation of SWEET transporters in plants: an update0 aStructure and regulation of SWEET transporters in plants an upda cNOV a1-60 v1563 a

Sugar will eventually be exported transporters (SWEETs), a novel family of sugar transporters found in both eukaryotes and prokaryotes, facilitate sugar flux across the cell membrane. Although these transporters were first discovered in plants, their homologs have been reported in different organisms. SWEETs have critical roles in various developmental processes, including phloem loading, nectar secretion, and pathogen nutrition. The structure of bacterial homologs, called SemiSWEETs, has been well studied thus far. Here, we provide an overview of SWEET protein structure and dynamic function by analyzing the solved crystal structures and predicted models that are available for a few SWEETs in a monocot plant (rice) and dicot plant (Arabidopsis thaliana). Despite the advancement in structure-related studies, the regulation of SWEETs remains unknown. In light of reported regulatory mechanisms of a few other sugar transporters, we propose the regulation of SWEETs at the post-translational level. We then enumerate the potential post-translational modification sites in SWEETs using computational tools. Overall, in this review, we critically analyze SWEET protein structure in plants to predict the post-translational regulation of SWEETs. Such findings have a direct bearing on plant nutrition and defense and targeting the regulation at these levels will be important in crop improvement.

10aoligomerization10aPhosphorylation10aPost-translational modification10aSugar transporters10aSugar will eventually be exported transporters1 aAnjali, Anjali1 aFatima, Urooj1 aManu, M., S.1 aRamasamy, Sureshkumar1 aSenthil-Kumar, Muthappa uhttps://library.ncl.res.in/content/structure-and-regulation-sweet-transporters-plants-update02473nas a2200253 4500008004100000022001400041245010500055210006900160260000900229300001200238490000800250520154700258653003701805653004501842653003101887653001901918653003601937653003001973100002202003700002202025700002202047700002002069856013002089 2022 eng d a0141-813000aAllosteric modulation of the chemokine receptor-chemokine CXCR4-CXCL12 complex by tyrosine sulfation0 aAllosteric modulation of the chemokine receptorchemokine CXCR4CX cMAY  a812-8220 v2063 a

The chemokine receptor CXCR4 and its cognate ligand CXCL12 mediate pathways that lead to cell migration and chemotaxis. Although the structural details of related receptor-ligand complexes have been resolved, the roles of the N-terminal domain of the receptor and post-translational sulfation that are determinants of ligand selectivity and affinity remain unclear. Here, we analyze the structural dynamics induced by receptor sulfation by combining molecular dynamics, docking and network analysis. The sulfotyrosine residues, 7YsN-term, 12Ys(N-term) and 21Ys(N-term) allow the N-terminal domain of the apo-sulfated receptor to adopt an ``open `` conformation that appears to facilitate ligand binding. The overall topology of the CXCR4-CXCL12 complex is independent of the sulfation state, but an extensive network of protein-protein interactions characterizes the sulfated receptor, in line with its increased ligand affinity. The altered interactions of sulfotyrosine residues, such as 21Ys(N-term)- 47R(CXCL12) replacing the 21Y(N-term)-13F(CXCL12) interaction, propagate via allosteric pathways towards the receptor lumen. In particular, our results suggest that the experimentally-reported receptor-ligand interactions 262D(6.58)- 8R(CXCL12) and 277E(7.28)-12R(CXCL12) could be dependent on the sulfation state of the receptor and need to be carefully analyzed. Our work is an important step in understanding chemokine-receptor interactions and how post-translational modifications could modulate receptor-ligand complexes.

10aAllosteric communication pathway10aAtomistic molecular dynamics simulations10aG protein-coupled receptor10aLigand binding10aPost-translational modification10aProtein-protein interface1 aSonawani, Archana1 aKharche, Shalmali1 aDasgupta, Debjani1 aSengupta, Durba uhttps://library.ncl.res.in/content/allosteric-modulation-chemokine-receptor-chemokine-cxcr4-cxcl12-complex-tyrosine-sulfation