01793nas a2200241 4500008004100000022001400041245013800055210006900193260007100262300001600333490000800349520084600357100002101203700002001224700002301244700002201267700002401289700002401313700002601337700003501363700002801398856012501426 2013 eng d a0002-786300aSynthetic zipper peptide motif orchestrated via co-operative interplay of hydrogen bonding, aromatic stacking, and backbone chirality0 aSynthetic zipper peptide motif orchestrated via cooperative inte a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a11477-114800 v1353 a

Here, we report on a new class of synthetic zipper peptide which assumes its three-dimensional zipper-like structure via a co-operative interplay of hydrogen bonding, aromatic stacking, and backbone chirality. Structural studies carried out in both solid- and solution-state confirmed the zipper-like structural architecture assumed by the synthetic peptide which makes use of unusually remote inter-residual hydrogen-bonding and aromatic stacking interactions to attain its shape. The effect of chirality modulation and the extent of noncovalent forces in the structure stabilization have also been comprehensively explored via single-crystal X-ray diffraction and solution-state NMR studies. The results highlight the utility of noncovalent forces in engineering complex synthetic molecules with intriguing structural architectures.

1 aNair, Roshna, V.1 aKheria, Sanjeev1 aRayavarapu, Suresh1 aKotmale, Amol, S.1 aJagadeesh, Bharatam1 aGonnade, Rajesh, G.1 aPuranik, Vedavati, G.1 aRajamohanan, Pattuparambil, R.1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/synthetic-zipper-peptide-motif-orchestrated-co-operative-interplay-hydrogen-bonding-001978nas a2200193 4500008004100000022001400041245007100055210006900126260011000195300001400305490000700319520123400326100002001560700002101580700002201601700003501623700002801658856009801686 2015 eng d a1144-054600aRole of N-terminal proline in stabilizing the Ant-Pro zipper motif0 aRole of Nterminal proline in stabilizing the AntPro zipper motif aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAR a3327-33320 v393 a

Hetero-chiral hybrid peptides of the general sequence (L)alpha beta(D)(n)alpha beta(n) featuring proline (Pro, a constrained alpha-amino acid) and anthranilic acid (Ant, a constrained beta-amino acid) as building blocks, where n = 2, 4 etc., form a three-dimensional zipper-like architecture. These zipper peptides attain stable conformation by balancing the co-operative contribution of two competing non-covalent forces, namely hydrogen bonding and aromatic stacking. However, the selection of the N-terminal residue also stands to be one of the key contributors in stabilising the unusually long-range intramolecular hydrogen bond, featuring 26 atoms in the H-bonded ring observed at the termini. This article deals with the substitution alterations at the N-terminus of the zipper motif and their consequent influences on its structure and stability. In this study, the N-terminal Pro residue of the zipper motif was substituted with a flexible amino acid, alanine, and a constrained acyclic amino acid, 2-aminoisobutyric acid, to investigate the role of N-terminal proline in stabilizing the Ant-Pro zipper motif, and its stabilities were assessed by employing solution-state NMR and restrained MD simulation studies.

1 aKheria, Sanjeev1 aNair, Roshna, V.1 aKotmale, Amol, S.1 aRajamohanan, Pattuparambil, R.1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/role-n-terminal-proline-stabilizing-ant-pro-zipper-motif-001184nas a2200193 4500008004100000245010500041210006900146260000800215300001400223490000700237520047500244100002000719700002300739700002200762700002300784700002400807700002800831856013100859 2017 eng d00aCoumarin-appended stable fluorescent self-complementary quadruple-hydrogen-bonded molecular duplexes0 aCoumarinappended stable fluorescent selfcomplementary quadrupleh cJUN a6403-64080 v823 aIn this paper we report a coumarin-conjugated self-assembling system adorned with valuable features such as high duplex stability and a built-in fluorophore, which would augment its application potential. This system forms a highly :stalik molecular duplex in a nonpolar solvent (K-dim > 1.9 X 10(7) M-1 in CDCl3). Due to the fluorescent property of coumarin, these new structural motifs may find potential application in material chemistry and supramolecular chemistry.1 aKheria, Sanjeev1 aRayavarapu, Suresh1 aKotmale, Amol, S.1 aShinde, Dinesh, R.1 aGonnade, Rajesh, G.1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/coumarin-appended-stable-fluorescent-self-complementary-quadruple-hydrogen-bonded-molecular01771nas a2200181 4500008004100000245011100041210006900152260000800221300001600229490000700245520108800252100002301340700002001363700002301383700002401406700002801430856013101458 2017 eng d00aModular approach towards functionalized highly stable self-complementary quadruple hydrogen bonded systems0 aModular approach towards functionalized highly stable selfcomple cDEC a10087-100940 v153 aSelf-complementary quadruple hydrogen bonded systems have shown potential as key building blocks for developing various supramolecular polymers. Opportunities for the introduction of multiple functionalities would further augment, in principle, their application potential. Herein, we report a novel modular approach to simultaneously introduce two closely aligned side chains into AADD-type self-complementary quadruple hydrogen-bonding systems. Dithiane-tethered ureidopyrimidinone has been used as a reactive intermediate to efficiently attach closely aligned side chains by simply reacting with amines to form highly stable molecular duplexes. These duplexes featuring AADD-type arrays of hydrogen bonding codes are highly stable in non-polar solvents (K-dim > 1.9 x 10(7) M-1 in CDCl3) as well as in polar solvents (K-dim > 10(5) in 10% DMSO-d(6)/CDCl3). Another notable feature of these self-assembling systems is their insensitivity to prototropy-related issues owing to their prototropic degeneracy, which will enhance their application potential in supramolecular chemistry.1 aRayavarapu, Suresh1 aKheria, Sanjeev1 aShinde, Dinesh, R.1 aGonnade, Rajesh, G.1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/modular-approach-towards-functionalized-highly-stable-self-complementary-quadruple-hydrogen01395nas a2200157 4500008004100000245014800041210006900189260000800258490000700266520074400273100002001017700002301037700002201060700002801082856012701110 2017 eng d00aThree in one: prototropy-free highly stable AADD-type self-complementary quadruple hydrogen-bonded molecular duplexes with built-in fluorophore0 aThree in one prototropyfree highly stable AADDtype selfcomplemen cFEB0 v533 aThis communication reports an effective approach for addressing the prototropy-related problems in heterocycle-based AADD-type self-assembling systems by freezing their hydrogen-bonding codes, by utilizing intramolecular bifurcated hydrogen bonding interactions. Using this strategy, we have also developed a hydroquinone-conjugated AADD-type self-assembling system adorned with three valuable features such as prototropy-free dimerization yielding single duplexes, high duplex stability and a built-in fluorophore, which would augment its application potential. The rational approach used herein to arrest prototropic shift may also find application elsewhere, wherein proton shift-mediated structural changes become a detrimental factor.1 aKheria, Sanjeev1 aRayavarapu, Suresh1 aKotmale, Amol, S.1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/three-one-prototropy-free-highly-stable-aadd-type-self-complementary-quadruple-hydrogen01064nas a2200181 4500008004100000245011700041210006900158260000800227300001200235490000700247520038000254100002000634700002300654700002200677700002400699700002800723856013100751 2017 eng d00aTriazine-based highly stable AADD-type self-complementary quadruple hydrogen-bonded systems devoid of prototropy0 aTriazinebased highly stable AADDtype selfcomplementary quadruple cJAN a783-7870 v233 a

A new class of 1,3,5-triazine-based quadruple hydrogen-bonded system featuring AADD-type self-complementary arrays has been developed and characterized. This system forms highly stable molecular duplex in non-polar solvent (K-dim > 1.9 x 10(7) M-1 in CDCl3) without prototropy-related issues, raising its prospects for application in supramolecular polymer science.

1 aKheria, Sanjeev1 aRayavarapu, Suresh1 aKotmale, Amol, S.1 aGonnade, Rajesh, G.1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/triazine-based-highly-stable-aadd-type-self-complementary-quadruple-hydrogen-bonded-systems