Journal of Peptide Science J. Peptide Sci. 9: 47–53 (2003) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/psc.431 HRMAS NMR Observation of β -Sheet Secondary Structure on a Water Swollen Solid Support PIERRE ROUSSELOT-PAILLEY, CHRISTOPHE BOUTILLON, JEAN-MICHEL WIERUSZESKI and GUY LIPPENS* UMR 8525 CNRS- Institut de Biologie de Lille - Universit ´ e de Lille II and Institut Pasteur de Lille, 1 rue du Professeur Calmette, BP447, 59021 Lille Cedex, France Received 22 February 2002 Accepted 1 July 2002 Abstract: In this paper HRMAS NMR was used to investigate whether peptides on a peptidyl resin swollen in aqueous solution can adopt an intramolecular β-sheet structure. A model peptide YQNPDGSQA, that was previously shown to adopt such a secondary structure in solution, (Blanco et al., J. Am. Chem. Soc., 1993) was grafted onto three different solid supports that swell in aqueous solution to examine the influence of the resin on the structure. Both parameters of resin loading and pH inside the swollen peptidyl resin proved to be important for the physicochemical behaviour of the peptide on the support. Copyright  2003 European Peptide Society and John Wiley & Sons, Ltd. Keywords: HRMAS NMR; peptide; solid phase peptide synthesis; secondary structure; intramolecular β-sheet INTRODUCTION The rules that underlie protein folding have been extensively studied by structural examination of small model peptides. Especially for the α-helix structure, these attempts have resulted in a num- ber of rules leading to the reliable prediction of this secondary structure element [1]. For the β sheet, however, the non-local nature of the interaction increases the difficulty of the problem. Moreover, the intermolecular aggregation that is often encoun- tered at the concentration needed for a detailed structural study has ruled out the study of many sequences. This latter phenomenon equally occurs in vivo, where partially unfolded polypeptides tend * Correspondence to: Dr Guy Lippens, UMR 8525 CNRS- Institut de Biologie de Lille - Universit´ e de Lille II and Institut Pasteur de Lille, 1 rue du Professeur Calmette, BP447, 59021 Lille Cedex, France; e-mail: guy.lippens@pasteur-lille.fr Contract/grant sponsor: European community (FEDER). Contract/grant sponsor: R´ egion Nord-Pas de Calais, France. Contract/grant sponsor: CNRS. Contract/grant sponsor: Institut Pasteur de Lille. Contract/grant sponsor: Ministry of Research and Technology, France. to aggregate to form fibres with an extensive β -sheet content, and leads to various molecular diseases known collectively under the name of amyloid dis- eases [2]. Preventing the aggregation of peptides can be done by various parameters such as temperature, pH, addition of co-solvent, but the simplest way is to decrease the concentration. In vivo, some chaperone proteins prevent the aggregation of par- tially unfolded peptides by sequestering them in a hydrophobic environment [3]. Chemical immobiliza- tion of the molecules can also be used to prevent aggregation, and has led to improved refolding of recombinant proteins [4] or the observation of the random coil to α-helix transition for a polystyrene resin tethered poly-alanine peptide in DMF [5]. This latter study showed the potential of resin anchoring combined with high resolution magic angle spinning (HRMAS) NMR [6] to study aggregating systems. Further experimental evidence of α-helical peptide structure on different supports that swell in aque- ous solution was reported for a viral peptide [7] and, very recently, for peptides corresponding to a trans- membrane helix [8]. Copyright  2003 European Peptide Society and John Wiley & Sons, Ltd.