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Book Chapter
Ligand based nuclear magnetic resonance screening techniques, Viegas, A., Macedo A. L., and Cabrita E. J. , Ligand Macromolecule Interactions in drug discovery, Methods in Molecular Biology, New York, p.81-100, (2010)
Theory and Application of NMR Diffusion Studies , Brand, T., Cabrita E. J., and Berger S. , Modern Magnetic Resonanc, p.131-139, (2006)
Journal Article
Antifungals on paper conservation: An overview , Sequeira, Sílvia, Cabrita Eurico J., and Macedo Filomena M. , International Biodeterioration & Biodegradation, Volume 74, p.67-84, (2012) Abstract

Since its invention, paper has become one of the main carriers of our cultural, scientific, political, economic and historical information. Given the importance of this material, its preservation is a matter of great interest. Paper can be deteriorated due to physical, chemical and biological agents. Within microorganisms, fungi are the major paper biodeteriogens. Throughout history, several methods have been used to prevent and stop fungal deterioration on paper based materials. In this work we present a review of the main chemical and physical methods used to avoid fungal paper biodeterioration until nowadays and also of some new approaches tested recently. The advantages and disadvantages of these methods are discussed as well as their health effects. Studies regarding antifungal compositions, methods of application, performance and effects on the treated materials are also presented with the aim of providing a clear set of conclusions on the topic. (C) 2012 Elsevier Ltd. All rights reserved.

Thymus mastichina: Chemical Constituents and their Anti-cancer Activity , Gordo, Joana, Máximo Patrícia, Cabrita Eurico, Lourenço Ana, Oliva Abel, Almeida Joana, Filipe Mariana, Cruz Pedro, Barcia Rita, Santos Miguel, and Cruz Helder , Natural Product Communications, Volume 7, Issue 11, p.1491-1494, (2012)
An Alternative Mechanism for Diels-Alder Reactions of Evans Auxiliary Derivatives, Bakalova, Snezhana M., Duarte Filipe J. S., Georgieva Miglena K., Cabrita Eurico J., and Santos Gil A. , Chemistry-a European Journal, 2009, Volume 15, Number 31, p.7665-7677, (2009) Abstract
Analysis of nucleotides binding to chromatography supports provided by nuclear magnetic resonance spectroscopy, Cruz, Carla, Cabrita Eurico J., and Queiroz Joao A. , Journal of Chromatography a, JUN 3 2011, Volume 1218, Number 22, p.3559-3564, (2011) Abstract
Application of diffusion-ordered spectroscopy for the analysis of cancer related biological samples, Ivanova, G. I., Cabrita E. J., O'Connor R., Eustace A. J., and Brougham D. F. , Bulgarian Chemical Communications, 2008, Volume 40, Number 4, p.464-468, (2008) Abstract
Application of HR-MAS NMR in the solid-phase synthesis of a glycopeptide using Sieber amide resin, Carvalho, Luisa R., Corvo Marta C., Enugala Ramu, Marques Manuel M. B., and Cabrita Eurico J. , Magnetic Resonance in Chemistry, APR 2010, Volume 48, Number 4, p.323-330, (2010) Abstract
Assessing diffusion in enzyme loaded sol–gel matrices, Barreira, Gustavo, Ferreira Ana S. D., Vidinha Pedro, Cabral Joaquim M. S., Martinho José M. G., Lima João Carlos, Cabrita Eurico J., and Barreiros Susana , RSC Advances, Volume 4, p.25099-25105, (2014) AbstractWebsite

Pulsed field gradient spin echo high resolution magic angle spinning nuclear magnetic resonance spectroscopy is a powerful technique to characterize confined biosystems. We used this approach to assess the diffusion of solvent and reaction species within sol–gel matrices differing in enzyme loading.

Asymmetric Intramolecular Aldol Reactions of Substituted 1,7-Dicarbonylic Compounds. A Mechanistic Study, Duarte, F. J. S., Cabrita E. J., Frenking G., and Santos Gil A. , Journal of Organic Chemistry, APR 16 2010, Volume 75, Number 8, p.2546-2555, (2010) Abstract
Binding analysis between l-histidine immobilized and oligonucleotides by SPR and NMR, Cruz, Carla, Santos Sandra D., Cabrita Eurico J., and Queiroz João A. , International Journal of Biological Macromolecules, Volume 56, p.175-180, (2013) AbstractWebsite

Saturation transfer difference (STD) NMR technique and surface plasmon resonance (SPR) are used to study amino acid affinity supports–nucleotides interactions with l-histidine amino acid immobilized on a surface as model support. We have immobilized l-histidine ligand on a carboxymethyldextran- modified gold surface intended for surface plasmon resonance and we analyze the binding profiles of synthetic polynucleotides (1–6 base, sugar and backbone) by determining the equilibrium dissociation constant (KD). The SPR binding profile (square-shaped) is identical for all the complexes and the highest binding affinity can be found for polyA6 followed by polyG6 . As expected, the 5′ -mononucleotides have the lowest affinity. To further study the structural aspects of the interaction we investigate the polynucleotide binding preferences to l-histidine chromatography support by STD-NMR spectroscopy. These results revealed that an increase in the number of bases and backbone to 6 units leads to more contacts with the support, where the main driving force for the interaction with polynucleotides are through the base, except for polyC6 , which is mainly through sugar-phosphate backbone. Therefore, the combination of SPR measurements with STD-NMR technique allowed to establish fine details of the molecular recognition process involved in amino acid affinity supports–nucleotides complexes.

Binding of ibuprofen, ketorolac and diclofenac to COX-1 and COX-2 studied by saturation transfer difference NMR, Viegas, Aldino, Manso Joao, Corvo Marta C., Marques Manuel M. B., and Cabrita Eurico J. , Journal of Medicinal Chemistry, Volume 54, Issue 24, p.8555-8562, (2011) AbstractWebsite

Saturation Transfer Difference-NMR (STD-NMR) spectroscopy has emerged as a powerful screening tool and a straightforward way to study the binding epitopes of active compounds in early stage lead discovery in pharmaceutical research. Here we report the application of STD NMR to characterize the binding of the anti-inflammatory drugs ibuprofen, diclofenac and ketorolac to COX-1 and COX-2. Using well-studied COX inhibitors and by comparing STD signals with crystallographic structures we show that there is a relation between the orientations of ibuprofen and diclofenac in the COX-2 active site and the relative STD responses detected in the NMR experiments. Based on this analysis we propose that ketorolac should bind to the COX-2 active site in similar orientation as that of diclofenac. We also show that the combination of STD NMR with competition experiments constitutes a valuable tool to address the recently proposed behavior of COX-2 as functional heterodimers and complement enzyme activity studies in the effort to rationalize COX inhibition mechanisms.

Biochemical, Stabilization and Crystallization Studies on a Molecular Chaperone (PaoD) Involved in the Maturation of Molybdoenzymes., Otelo-Cardoso, AR, Schwuchow V., Rodrigues D., Cabrita E. J., Leimkühler S., Romão MJ, and Santos-Silva T. , PLoS One, Volume 9, p.e87295 , (2014) AbstractWebsite

Molybdenum and tungsten enzymes require specific chaperones for folding and cofactor insertion. PaoD is the chaperone of the periplasmic aldehyde oxidoreductase PaoABC. It is the last gene in the paoABCD operon in Escherichia coli and its presence is crucial for obtaining mature enzyme. PaoD is an unstable, 35 kDa, protein. Our biochemical studies showed that it is a dimer in solution with a tendency to form large aggregates, especially after freezing/thawing cycles. In order to improve stability, PaoD was thawed in the presence of two ionic liquids [C4mim]Cl and [C2OHmim]PF6 and no protein precipitation was observed. This allowed protein concentration and crystallization using polyethylene glycol or ammonium sulfate as precipitating agents. Saturation transfer difference – nuclear magnetic resonance (STD-NMR) experiments have also been performed in order to investigate the effect of the ionic liquids in the stabilization process, showing a clear interaction between the acidic ring protons of the cation and, most likely, negatively charged residues at the protein surface. DLS assays also show a reduction of the overall size of the protein aggregates in presence of ionic liquids. Furthermore, cofactor binding studies on PaoD showed that the protein is able to discriminate between molybdenum and tungsten bound to the molybdenum cofactor, since only a Mo-MPT form of the cofactor remained bound to PaoD.

Boron trifluoride catalyzed polymerisation of 2-substituted-2-oxazolines in supercritical carbon dioxide, de Macedo, Carlota Veiga, da Silva Mara Soares, Casimiro Teresa, Cabrita Eurico J., and Aguiar-Ricardo Ana , Green Chemistry, 2007, Volume 9, Number 9, p.948-953, (2007) Abstract
Characterization of reactive intermediates by diffusion-ordered NMR spectroscopy: A snapshot of the reaction of (CO2)-C-13 with [Cp2Zr(Cl)H], Schlorer, NE, Cabrita E. J., and Berger S. , Angewandte Chemie-International Edition, 2002, Volume 41, Number 1, p.107-109, (2002) Abstract
Deacidification of paper using dispersions of Ca(OH)(2) nanoparticles in isopropanol. Study of efficiency, Sequeira, S., Casanova C., and Cabrita E. J. , Journal of Cultural Heritage, OCT-DEC 2006, Volume 7, Number 4, p.264-272, (2006) Abstract
Delineating binding modes of Gal/GalNAc and structural elements of the molecular recognition of tumor-associated mucin glycopeptides by the human macrophage galactose-type lectin, Marcelo, Filipa, Garcia-Martin Fayna, Matsushita Takahiko, Sardinha João, Coelho Helena, Oude-Vrielink Anneloes, Koller Christiane, André Sabine, Cabrita Eurico J., Gabius Hans-Joachim, Nishimura Shin-Ichiro, Jiménez-Barbero Jesús, and Cañada Javier F. , Chem. Eur. J., Volume in press, (2014) Abstract

The human macrophage galactose-type lectin (hMGL) is a key physiological receptor for the carcinoma-associated Tn antigen (GalNAc-α-1-O-Ser/Thr) in mucins. We herein report NMR- and modeling-based data on the molecular recognition features of synthetic Tn-bearing glycopeptides by hMGL. Cognate epitopes on the sugar and matching key amino acids involved in the interaction have been identified by saturation transfer difference (STD) NMR spectroscopy. Only the amino acids close to the glycosylation site in the peptides are involved in lectin contact. Moreover, control experiments with non-glycosylated MUC1 peptides unequivocally showed that the sugar residue is essential for hMGL binding, as is Ca2+. The dissociation constants (Kd) have been estimated by STD titrations and/or STD competition experiments and show that Gal was a poor binder for hMGL, with a Kd in the mM range, while GalNAc and MUC1 Tn-glycopetides reached Kd values in the lower μM range. STD-based results suggested a distinct interacting epitope for the two monosaccharides. NMR data have been complemented with molecular dynamics simulations and Corcema- ST to establish a 3D view on the molecular recognition process between Gal, GalNAc and the Tn-presenting glycopeptides and hMGL. Gal and GalNAc have a dual binding mode with opposite trend of the main interaction pattern and the differences in affinity can be explained by additional hydrogen bonds and CH-π contacts involving exclusively the NHAc moiety.

Density Functional Study of Proline-Catalyzed Intramolecular Baylis-Hillman Reactions, Duarte, Filipe J. S., Cabrita Eurico J., Frenking Gernot, and Santos Gil A. , Chemistry-a European Journal, 2009, Volume 15, Number 7, p.1734-1746, (2009) Abstract
Development of molecularly imprinted co-polymeric devices for controlled delivery of flufenamic acid using supercritical fluid technology, da Silva, Mara Soares, Nobrega Franklin L., Aguiar-Ricardo Ana, Cabrita Eurico J., and Casimiro Teresa , Journal of Supercritical Fluids, AUG 2011, Volume 58, Number 1, p.150-157, (2011) Abstract
Development of PMMA membranes functionalized with hydroxypropyl-beta-cyclodextrins for controlled drug delivery using a supercritical CO(2)-assisted technology, Temtem, M., Pompeu D., Jaraquemada G., Cabrita E. J., Casimiro T., and Aguiar-Ricardo A. , International Journal of Pharmaceutics, JUL 6 2009, Volume 376, Number 1-2, p.110-115, (2009) Abstract
DOSY studies of hydrogen bond association: tetramethylsilane as a reference compound for diffusion studies, Cabrita, E. J., and Berger S. , Magnetic Resonance in Chemistry, DEC 2001, Volume 39, p.S142-S148, (2001) Abstract
Epitope mapping of imidazolium cations in ionic liquid–protein interactions unveils the balance between hydrophobicity and electrostatics towards protein destabilisation, Silva, Micael, Figueiredo Angelo Miguel, and Cabrita Eurico J. , Phys. Chem. Chem. Phys. , Volume in press, (2014) Abstract

We investigated imidazolium-based ionic liquid (IL) interactions with human serum albumin (HSA) to discern the level of cation interactions towards protein stability. STD-NMR spectroscopy was used to observe the imidazolium IL protons involved in direct binding and to identify the interactions responsible for changes in Tm as accessed by differential scanning calorimetry (DSC). Cations influence protein stability less than anions but still significantly. It was found that longer alkyl side chains of imidazolium- based ILs (more hydrophobic) are associated with a higher destabilisation effect on HSA than short-alkyl groups (less hydrophobic). The reason for such destabilisation lies on the increased surface contact area of the cation with the protein, particularly on the hydrophobic contacts promoted by the terminus of the alkyl chain. The relevance of the hydrophobic contacts is clearly demonstrated by the introduction of a polar moiety in the alkyl chain: a methoxy or alcohol group. Such structural modification reduces the degree of hydrophobic contacts with HSA explaining the lesser extent of protein destabilisation when compared to longer alkyl side chain groups: above [C2mim]+. Competition STD-NMR experiments using [C2mim]+, [C4mim]+ and [C2OHmim]+ also validate the importance of the hydrophobic interactions. The combined effect of cation and anion interactions was explored using 35Cl NMR. Such experiments show that the nature of the cation has no influence on the anion–protein contacts, still the nature of the anion modulates the cation–protein interaction. Herein we propose that more destabilising anions are likely to be a result of a partial contribution from the cation as a direct consequence of the different levels of interaction (cation–anion pair and cation–protein).

Exploratory applications of diffusion ordered spectroscopy to liquid foods: an aid towards spectral assignment, Gil, A. M., Duarte I., Cabrita E., Goodfellow BJ, Spraul M., and Kerssebaum R. , Analytica Chimica Acta, MAR 24 2004, Volume 506, Number 2, p.215-223, (2004) Abstract
Flexible molecules with defined shape. X. Synthesis and conformational study of 1,5-diaza-cis-decalin, Santos, AGD, Klute W., Torode J., Bohm V. P. W., Cabrita E., Runsink J., and Hoffmann RW , New Journal of Chemistry, SEP 1998, Volume 22, Number 9, p.993-997, (1998) Abstract
High-pressure NMR characterization of triacetyl-beta-cyclodextrin in supercritical carbon dioxide, Ivanova, G. I., Vao E. R., Temtem M., Aguiar-Ricardo A., Casimiro T., and Cabrita E. J. , Magnetic Resonance in Chemistry, FEB 2009, Volume 47, Number 2, p.133-141, (2009) Abstract