@article { ISI:000241179400014, title = {Hybrid foldamer with unique architecture from conformationally constrained aliphatic-aromatic amino acid conjugate}, journal = {Tetrahedron}, volume = {62}, number = {43}, year = {2006}, month = {OCT}, pages = {10141-10146}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

In this paper, we describe the design and synthesis of a novel hybrid foldamer, derived from a conformationally constrained aliphatic-aromatic amino acid conjugate that adopts a well-defined, compact, three-dimensional structure, governed by a combined conformational restriction imposed by the individual amino acids from which the foldamer is composed. Conformational investigations confirmed the prevalence of a unique doubly bent conformation for the foldamer, in both solid and solution states, as evidenced from single crystal X-ray and 2D NOESY studies, respectively. The findings suggest that constrained aliphatic-aromatic amino acid conjugates offer new avenues for the de novo design of hybrid foldamers with distinctive structural architectures. Furthermore, the de novo design strategy disclosed herein has the potential for significantly augmenting the {\textquoteleft}tool-box{\textquoteright} of the modern day peptidominetic chemist, as well as providing a novel approach to the field of rational design. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {Amino acids, Conformation, Foldamer, Peptidomimetics}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.08.032}, author = {Srinivas, Deekonda and Gonnade, Rajesh G. and Ravindranathan, Sapna and Sanjayan, Gangadhar J.} } @article { ISI:000320036300013, title = {Ant-pro reverse-turn motif. structural features and conformational characteristics}, journal = {European Journal of Organic Chemistry}, number = {17, SI}, year = {2013}, month = {JUN}, pages = {3529-3542}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

This article details the characteristic conformational features of the Ant-Pro reverse turn ? a folded pseudo -turn motif that displays a closed nine-membered-ring hydrogen-bonded network involving just two amino acid residues, namely anthranilic acid (Ant; a constrained -amino acid), and proline (Pro; a constrained -amino acid). The results from the extensive investigation of ten crystal structures and their NMR conformations in the solution state provide a clear idea about the conformational characteristics of the Ant-Pro reverse turn. The Ant and Pro residues, which form the turn segment, maintain a perfect antiperiplanar orientation throughout, leaving little possibility for the formation of the otherwise possible six-membered hydrogen-bonding that requires a coplanar disposition of the two amino acid residues, as clearly evident from investigation of several crystal structures. The closed hydrogen-bonded network observed in the Ant-Pro reverse turn motif, formed in the forward direction of the sequence (12 amino acid interactions) involving only two amino acid residues, is in stark contrast to the native -turns that involve four residues to form hydrogen-bonded network featuring backward 14 amino acid interactions. The readily available two-residue Ant-Pro motif raises the possibility of a practical utility, particularly in the application of rigidifying flexible peptide backbones by inserting the robust Ant-Pro reverse turn motifs into their backbone.

}, keywords = {Peptides, Peptidomimetics, Protein folding, Protein structures}, issn = {1434-193X}, doi = {10.1002/ejoc.201201739}, author = {Thorat, Vijaykumar H. and Ingole, Tukaram S. and Vijayadas, Kuruppanthara N. and Nair, Roshna V. and Kale, Sangram S. and Ramesh, Veera V. E. and Davis, Hilda C. and Prabhakaran, Panchami and Gonnade, Rajesh G. and Gawade, Rupesh L. and Puranik, Vedavati G. and Rajamohanan, Pattuparambil R. and Sanjayan, Gangadhar J.} } @article { ISI:000372848000021, title = {Disruption of native beta-turns: consequence of folding competition between native and orthanilic acid proline-based pseudo beta-turn}, journal = {European Journal of Organic Chemistry}, number = {7}, year = {2016}, month = {MAR}, pages = {1380-1388}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Five tetrapeptides comprising beta-turn-forming elements and a pseudo beta-turn (C9 H-bonding) based on an SAntPro (orthanilic acid - proline) motif were designed and synthesized. Their extensive conformational investigation by single-crystal X-ray crystallography, solution-state 2D NMR spectroscopic, and nOe-restrained MD simulation studies revealed the formation of C14 or C9 folding and disruption of the native beta-turn (C10 H-bonding) architecture. The striking difference between the psi(psi(2)) angle of {\textquoteleft}{\textquoteleft}i + 2{\textquoteright}{\textquoteright} residues of native beta-turn and designed peptides suggest that formation of the native beta-turn is not favored. The results suggest that other turn-forming motifs can dramatically modulate the stability of the native beta-turn structure.

}, keywords = {Conformation analysis, hydrogen bonds, Peptidomimetics, structure elucidation}, issn = {1434-193X}, doi = {10.1002/ejoc.201501558}, author = {Ingole, Tukaram S. and Vijayadas, Kuruppanthara N. and Chaitanya, K. N. and Kotmale, Amol S. and Gawade, Rupesh L. and Gonnade, Rajesh G. and Rajamohanan, P. R. and Sanjayan, Gangadhar J.} }