Structural insights into Siglec-15 reveal glycosylation dependency for its interaction with T cells through integrin CD11b.

Sialic acid-binding Ig-like lectin 15 (Siglec-15) is an immune modulator and emerging cancer immunotherapy target. However, limited understanding of its structure and mechanism of action restrains the development of drug candidates that unleash its full therapeutic potential. In this study, we elucidate the crystal structure of Siglec-15 and its binding epitope via co-crystallization with an anti-Siglec-15 blocking antibody. Using saturation transfer-difference nuclear magnetic resonance (STD-NMR) spectroscopy and molecular dynamics simulations, we reveal Siglec-15 binding mode to α(2,3)- and α(2,6)-linked sialic acids and the cancer-associated sialyl-Tn (STn) glycoform. We demonstrate that binding of Siglec-15 to T cells, which lack STn expression, depends on the presence of α(2,3)- and α(2,6)-linked sialoglycans. Furthermore, we identify the leukocyte integrin CD11b as a Siglec-15 binding partner on human T cells. Collectively, our findings provide an integrated understanding of the structural features of Siglec-15 and emphasize glycosylation as a crucial factor in controlling T cell responses.

Atomic and Specificity Details of Mucin 1 O-Glycosylation Process by Multiple Polypeptide GalNAc-Transferase Isoforms Unveiled by NMR and Molecular Modeling.

The large family of polypeptide GalNAc-transferases (GalNAc-Ts) controls with precision how GalNAc O-glycans are added in the tandem repeat regions of mucins (e.g., MUC1). However, the structural features behind the creation of well-defined and clustered patterns of O-glycans in mucins are poorly understood. In this context, herein, we disclose the full process of MUC1 O-glycosylation by GalNAc-T2/T3/T4 isoforms by NMR spectroscopy assisted by molecular modeling protocols. By using MUC1, with four tandem repeat domains as a substrate, we confirmed the glycosylation preferences of different GalNAc-Ts isoforms and highlighted the importance of the lectin domain in the glycosylation site selection after the addition of the first GalNAc residue. In a glycosylated substrate, with yet multiple acceptor sites, the lectin domain contributes to orientate acceptor sites to the catalytic domain. Our experiments suggest that during this process, neighboring tandem repeats are critical for further glycosylation of acceptor sites by GalNAc-T2/T4 in a lectin-assisted manner. Our studies also show local conformational changes in the peptide backbone during incorporation of GalNAc residues, which might explain GalNAc-T2/T3/T4 fine specificities toward the MUC1 substrate. Interestingly, we postulate that a specific salt-bridge and the inverse γ-turn conformation of the PDTRP sequence in MUC1 are the main structural motifs behind the GalNAc-T4 specificity toward this region. In addition, in-cell analysis shows that the GalNAc-T4 isoform is the only isoform glycosylating the Thr of the immunogenic epitope PDTRP in vivo, which highlights the relevance of GalNAc-T4 in the glycosylation of this epitope. Finally, the NMR methodology established herein can be extended to other glycosyltransferases, such as C1GalT1 and ST6GalNAc-I, to determine the specificity toward complex mucin acceptor substrates.

Structural Insights into the Molecular Recognition Mechanism of the Cancer and Pathogenic Epitope, LacdiNAc by Immune-Related Lectins.

Interactions of glycan-specific epitopes to human lectin receptors represent novel immune checkpoints for investigating cancer and infection diseases. By employing a multidisciplinary approach that combines isothermal titration calorimetry, NMR spectroscopy, molecular dynamics simulations, and X-ray crystallography, we investigated the molecular determinants that govern the recognition of the tumour and pathogenic glycobiomarker LacdiNAc (GalNAcß1-4GlcNAc, LDN), including their comparison with the ubiquitous LacNAc epitope (Galß1-4GlcNAc, LN), by two human immune-related lectins, galectin-3 (hGal-3) and the macrophage galactose C-type lectin (hMGL). A different mechanism of binding and interactions was observed for the hGal-3/LDN and hMGL/LDN complexes, which explains the remarkable difference in the binding specificity of LDN and LN by these two lectins. The new structural clues reported herein are fundamental for the chemical design of mimetics targeting hGal-3/hMGL recognition process.

Crystal Structure of the Carbohydrate Recognition Domain of the Human Macrophage Galactose C-Type Lectin Bound to GalNAc and the Tumor-Associated Tn Antigen.

The human macrophage galactose lectin (MGL) is an endocytic type II transmembrane receptor expressed on immature monocyte-derived dendritic cells and activated macrophages and plays a role in modulating the immune system in response to infections and cancer. MGL contains an extracellular calcium-dependent (C-type) carbohydrate recognition domain (CRD) that specifically binds terminal N-acetylgalactosamine glycan residues such as the Tn and sialyl-Tn antigens found on tumor cells, as well as other N- and O-glycans displayed on certain viruses and parasites. Even though the glycan specificity of MGL is known and several binding glycoproteins have been identified, the molecular basis for substrate recognition has remained elusive due to the lack of high-resolution structures. Here we present crystal structures of the MGL CRD at near endosomal pH and in several complexes, which reveal details of the interactions with the natural ligand, GalNAc, the cancer-associated Tn-Ser antigen, and a synthetic GalNAc mimetic ligand. Like the asialoglycoprotein receptor, additional calcium atoms are present and contribute to stabilization of the MGL CRD fold. The structure provides the molecular basis for preferential binding of N-acetylgalactosamine over galactose and prompted the re-evaluation of the binding modes previously proposed in solution. Saturation transfer difference nuclear magnetic resonance data acquired using the MGL CRD and interpreted using the crystal structure indicate a single binding mode for GalNAc in solution. Models of MGL1 and MGL2, the mouse homologues of MGL, explain how these proteins might recognize LewisX and GalNAc, respectively.

Structural characterization of an unprecedented lectin-like antitumoral anti-MUC1 antibody.

The molecular basis of antibody 5E5, which recognizes the entire GalNAc unit as a primary epitope is disclosed. The antibody's contacts with the peptide are mostly limited to two residues, allowing it to show some degree of promiscuity. These findings open the door to the chemical design of peptide-mimetics for developing efficient anti-cancer vaccines and diagnostic tools.

Molecular basis for fibroblast growth factor 23 O-glycosylation by GalNAc-T3.

Polypeptide GalNAc-transferase T3 (GalNAc-T3) regulates fibroblast growth factor 23 (FGF23) by O-glycosylating Thr178 in a furin proprotein processing motif RHT178R↓S. FGF23 regulates phosphate homeostasis and deficiency in GALNT3 or FGF23 results in hyperphosphatemia and familial tumoral calcinosis. We explored the molecular mechanism for GalNAc-T3 glycosylation of FGF23 using engineered cell models and biophysical studies including kinetics, molecular dynamics and X-ray crystallography of GalNAc-T3 complexed to glycopeptide substrates. GalNAc-T3 uses a lectin domain mediated mechanism to glycosylate Thr178 requiring previous glycosylation at Thr171. Notably, Thr178 is a poor substrate site with limiting glycosylation due to substrate clashes leading to destabilization of the catalytic domain flexible loop. We suggest GalNAc-T3 specificity for FGF23 and its ability to control circulating levels of intact FGF23 is achieved by FGF23 being a poor substrate. GalNAc-T3's structure further reveals the molecular bases for reported disease-causing mutations. Our findings provide an insight into how GalNAc-T isoenzymes achieve isoenzyme-specific nonredundant functions.

The Plasticity of the Carbohydrate Recognition Domain Dictates the Exquisite Mechanism of Binding of Human Macrophage Galactose-Type Lectin.

The human macrophage galactose-type lectin (MGL), expressed on macrophages and dendritic cells (DCs), modulates distinct immune cell responses by recognizing N-acetylgalactosamine (GalNAc) containing structures present on pathogens, self-glycoproteins, and tumor cells. Herein, NMR spectroscopy and molecular dynamics (MD) simulations were used to investigate the structural preferences of MGL against different GalNAc-containing structures derived from the blood group A antigen, the Forssman antigen, and the GM2 glycolipid. NMR spectroscopic analysis of the MGL carbohydrate recognition domain (MGL-CRD, C181-H316) in the absence and presence of methyl α-GalNAc (α-MeGalNAc), a simple monosaccharide, shows that the MGL-CRD is highly dynamic and its structure is strongly altered upon ligand binding. This plasticity of the MGL-CRD structure explains the ability of MGL to accommodate different GalNAc-containing molecules. However, key differences are observed in the recognition process depending on whether the GalNAc is part of the blood group A antigen, the Forssman antigen, or GM2-derived structures. These results are in accordance with molecular dynamics simulations that suggest the existence of a distinct MGL binding mechanism depending on the context of GalNAc moiety presentation. These results afford new perspectives for the rational design of GalNAc modifications that fine tune MGL immune responses in distinct biological contexts, especially in malignancy.

Novel carboxylate-based glycolipids: TLR4 antagonism, MD-2 binding and self-assembly properties.

New monosaccharide-based lipid A analogues were rationally designed through MD-2 docking studies. A panel of compounds with two carboxylate groups as phosphates bioisosteres, was synthesized with the same glucosamine-bis-succinyl core linked to different unsaturated and saturated fatty acid chains. The binding of the synthetic compounds to purified, functional recombinant human MD-2 was studied by four independent methods. All compounds bound to MD-2 with similar affinities and inhibited in a concentration-dependent manner the LPS-stimulated TLR4 signaling in human and murine cells, while being inactive as TLR4 agonists when provided alone. A compound of the panel was tested in vivo and was not able to inhibit the production of proinflammatory cytokines in animals. This lack of activity is probably due to strong binding to serum albumin, as suggested by cell experiments in the presence of the serum. The interesting self-assembly property in solution of this type of compounds was investigated by computational methods and microscopy, and formation of large vesicles was observed by cryo-TEM microscopy.

A phytochemical study of the Cuphea glutinosa from Southern Brazil: Na+,K+-ATPase activity inhibition and antioxidant properties.

This study investigated the antioxidant activity of Cuphea glutinosa (CG) and its effect on Na+, K+-ATPase from cardiac muscle. The ethanolic extract showed higher antioxidant capacity compared to aqueous and ethyl acetate fraction. Ethyl acetate fraction showed ß-sitosterol-3-O-ß-glucoside, kaempferol, quercetin, isoquercetin, gallic acid methyl ester, and gallic acid. The ethanolic extract also reduced the Na+,K+-ATPase activity. CG presented a promising antioxidant activity and inhibitory effect on the Na+, K+-ATPase activity, supporting biochemical evidences the popular use of this plant in the treatment of heart failure.

Structural and Mechanistic Insights into the Catalytic-Domain-Mediated Short-Range Glycosylation Preferences of GalNAc-T4.

Mucin-type O-glycosylation is initiated by a family of polypeptide GalNAc-transferases (GalNAc-Ts) which are type-II transmembrane proteins that contain Golgi luminal catalytic and lectin domains that are connected by a flexible linker. Several GalNAc-Ts, including GalNAc-T4, show both long-range and short-range prior glycosylation specificity, governed by their lectin and catalytic domains, respectively. While the mechanism of the lectin-domain-dependent glycosylation is well-known, the molecular basis for the catalytic-domain-dependent glycosylation of glycopeptides is unclear. Herein, we report the crystal structure of GalNAc-T4 bound to the diglycopeptide GAT*GAGAGAGT*TPGPG (containing two α-GalNAc glycosylated Thr (T*), the PXP motif and a "naked" Thr acceptor site) that describes its catalytic domain glycopeptide GalNAc binding site. Kinetic studies of wild-type and GalNAc binding site mutant enzymes show the lectin domain GalNAc binding activity dominates over the catalytic domain GalNAc binding activity and that these activities can be independently eliminated. Surprisingly, a flexible loop protruding from the lectin domain was found essential for the optimal activity of the catalytic domain. This work provides the first structural basis for the short-range glycosylation preferences of a GalNAc-T.

Structural Analysis of a GalNAc-T2 Mutant Reveals an Induced-Fit Catalytic Mechanism for GalNAc-Ts.

The family of polypeptide N-acetylgalactosamine (GalNAc) transferases (GalNAc-Ts) orchestrates the initiating step of mucin-type protein O-glycosylation by transfer of GalNAc moieties to serine and threonine residues in proteins. Deficiencies and dysregulation of GalNAc-T isoenzymes are related to different diseases. Recently, it has been demonstrated that an inactive GalNAc-T2 mutant (F104S), which is not located at the active site, induces low levels of high-density lipoprotein cholesterol (HDL-C) in humans. Herein, the molecular basis for F104S mutant inactivation has been deciphered. Saturation transfer difference NMR spectroscopy experiments demonstrate that the mutation induces loss of binding to peptide substrates. Analysis of the crystal structure of the F104S mutant bound to UDP-GalNAc (UDP=uridine diphosphate), combined with molecular dynamics (MD) simulations, has revealed that the flexible loop is disordered and displays larger conformational changes in the mutant enzyme than that in the wild-type (WT) enzyme. 19 F NMR spectroscopy experiments reveal that the WT enzyme only reaches the active state in the presence of UDP-GalNAc, which provides compelling evidence that GalNAc-T2 adopts a UDP-GalNAc-dependent induced-fit mechanism. The F104S mutation precludes the enzyme from achieving the active conformation and concomitantly binding peptide substrates. This study provides new insights into the catalytic mechanism of the large family of GalNAc-Ts and how these enzymes orchestrate protein O-glycosylation.

The interdomain flexible linker of the polypeptide GalNAc transferases dictates their long-range glycosylation preferences.

The polypeptide GalNAc-transferases (GalNAc-Ts), that initiate mucin-type O-glycosylation, consist of a catalytic and a lectin domain connected by a flexible linker. In addition to recognizing polypeptide sequence, the GalNAc-Ts exhibit unique long-range N- and/or C-terminal prior glycosylation (GalNAc-O-Ser/Thr) preferences modulated by the lectin domain. Here we report studies on GalNAc-T4 that reveal the origins of its unique N-terminal long-range glycopeptide specificity, which is the opposite of GalNAc-T2. The GalNAc-T4 structure bound to a monoglycopeptide shows that the GalNAc-binding site of its lectin domain is rotated relative to the homologous GalNAc-T2 structure, explaining their different long-range preferences. Kinetics and molecular dynamics simulations on several GalNAc-T2 flexible linker constructs show altered remote prior glycosylation preferences, confirming that the flexible linker dictates the rotation of the lectin domain, thus modulating the GalNAc-Ts' long-range preferences. This work for the first time provides the structural basis for the different remote prior glycosylation preferences of the GalNAc-Ts.

Utilização de medicamentos antes e durante a gestação: prevalência e fatores associados / Use of medicines before and during pregnancy: prevalence and associated factors / Utilización de medicamentos antes y durante la gestación: prevalencia y factores asociados

Resumo: Estudo transversal aninhado à coorte prospectiva com o objetivo de avaliar a prevalência e os fatores associados à utilização de medicamentos em gestantes antes e durante a gravidez em município do interior da Bahia, Brasil. As informações foram coletadas mediante um questionário estruturado aplicado às gestantes no momento do acompanhamento pré-natal em unidades de saúde do município. A prevalência para consumo de medicamentos antes e durante a gestação foi 52,1% e 84,7%, respectivamente. Após análise, os seguintes fatores estavam associados à utilização de medicamentos antes da gestação: ≥ 30 anos de idade, as não pretas, as que iniciaram o pré-natal depois do 1º trimestre e as que fazem parte da classe econômica C/D/E. Há um aumento de prevalência de utilização de medicamentos durante a gestação entre as gestantes com escolaridade ≥ 11 anos de estudo, ter feito mais de três consultas pré-natais e ter algum problema de saúde. As gestantes estão expostas ao uso de medicamentos antes e durante a gestação apesar da carência de informações seguras que fundamentem o uso de medicamentos nessa fase, e esse uso está associado a fatores relativos ao acompanhamento pré-natal, sugerindo-se a inclusão mais ativa do farmacêutico na equipe para orientação e apoio ao uso racional de medicamentos.

Abstract: This cross-sectional prospective nested cohort study aimed to assess the prevalence of use of medication before and during pregnancy and associated factors in women in a municipality in the countryside of Bahia State, Brazil. Data were collected with a structured questionnaire applied to pregnant women at their prenatal visits at health units. Prevalence rates for use of medication before and during pregnancy were 52.1% and 84.7%, respectively. The following were associated with use of medication before pregnancy: age ≥ 30 years, non-white skin color, first prenatal visit after the 1st trimester, and economic classes C/D/E. There was an increase in medication during pregnancy among women with ≥ 11 years of schooling, women with more than three prenatal visits, and those with some health problem. Pregnant women are exposed to medication before and during pregnancy, notwithstanding the lack of secure information to back the use of medicines during this phase; such use is associated with factors pertaining to prenatal follow-up, suggesting the need for more active participation by pharmacists in orientation and support for rational use of medicines.

Resumen: Estudio transversal situado en una cohorte prospectiva, con el objetivo de evaluar la prevalencia y factores asociados a la utilización de medicamentos en gestantes antes y durante el embarazo en un municipio del interior de la región de Bahía, Brasil. La información fue recogida mediante un cuestionario estructurado, aplicado a las embarazadas en el momento del seguimiento prenatal en unidades de salud del municipio. La prevalencia para el consumo de medicamentos antes y durante la gestación fue un 52,1% y un 84,7%, respectivamente. Tras el análisis, los siguientes factores estaban asociados a la utilización de medicamentos antes de la gestación: ≥ 30 años de edad; no afro-brasileñas; quienes comenzaron con el seguimiento prenatal tras el 1º trimestre, y las que forman parte de la clase económica C/D/E. Existe un aumento de prevalencia de utilización de medicamentos durante la gestación entre las gestantes con una escolaridad ≥ 11 años de estudio, haber realizado más de tres consultas prenatales y que tengan algún problema de salud. Las gestantes están expuestas al uso de medicamentos antes y durante la gestación, a pesar de la carencia de información segura que fundamente el uso de medicamentos en esa fase, y ese uso está asociado a factores relativos al seguimiento prenatal, sugiriéndose la inclusión más activa del farmacéutico en el equipo para la orientación y apoyo al uso racional de medicamentos.

Perfil dos ensaios clínicos envolvendo crianças brasileiras / Profile of clinical trials enrolling Brazilian children / Perfil de los ensayos clínicos involucrando niños brasileños

Resumo: Este estudo visou a caracterizar os ensaios clínicos com medicamentos envolvendo crianças e adolescentes brasileiros, registrados nas bases de dados do Clinical Trials e da Registro Brasileiro de Ensaios Clínicos (ReBEC), entre os anos de 1994 e 2014. Apenas 462 ensaios clínicos envolveram brasileiros nessa faixa etária. A partir de 2003, houve aumento no número de registros, com expressiva queda em 2011. Dentre esses, 35,5% foram sediados no Brasil. Os ensaios clínicos internacionais foram majoritariamente conduzidos por empresas norte-americanas. Em ambos os casos, a indústria multinacional foi a principal fonte de apoio financeiro. Predominaram ensaios clínicos de fase III com antivirais em formas farmacêuticas injetáveis e sólidas orais. Os ensaios clínicos nacionais apresentaram maior variação quanto às formas farmacêuticas e maior porcentual de formulações líquidas investigadas, em comparação aos internacionais. Além da forte dependência externa para a realização dos ensaios clínicos, destacou-se o desafio para o cuidado pediátrico no Brasil, que apresenta peculiaridades epidemiológicas em um ambiente propício ao uso de medicamentos não licenciados para crianças.

Abstract: This study aimed to characterize the clinical trials with medicines enrolling Brazilian children and adolescents, registered in the databases of Clinical Trials and the Brazilian Clinical Trials Network (ReBEC) from 1994 to 2014. Only 462 clinical trials enrolled Brazilian children and adolescents. There was an increase in registrations beginning in 2003, with an important drop in 2011. Among these trials, 35.5% were hosted in Brazil. The international clinical trials were mostly conducted by North American companies. In both cases, multinational industry was the principal source of funding. The clinical trials were predominantly phase III with injectable and solid oral pharmaceutical forms of antiviral drugs. Domestic clinical trials showed wider variation in the pharmaceutical forms and higher percentage of liquid formulations, when compared to the international trials. In addition to heavy external dependence for conducting clinical trials, the study emphasized the challenge for pediatric care in Brazil, which presents epidemiological peculiarities in an environment prone to the use of unlicensed medicines for children.

Resumen: Este estudio tuvo como objetivo caracterizar los ensayos clínicos con medicamentos, involucrando a niños y adolescentes brasileños, registrados en las bases de datos de Clinical Trials y de la Red Brasileña de Ensayos Clínicos (ReBEC), entre los años de 1994 y 2014. Solamente 462 ensayos clínicos involucraron a brasileños en esa franja de edad. A partir de 2003, hubo un aumento en el número de registros, con una expresiva caída en 2011. Entre ellos, un 35,5% estuvieron ubicados en Brasil. Los ensayos clínicos internacionales fueron mayoritariamente dirigidos por empresas norteamericanas. En ambos casos, la industria multinacional fue la principal fuente de apoyo financiero. Predominaron ensayos clínicos de fase III con antivirales en formas farmacéuticas inyectables y orales sólidas. Los ensayos clínicos nacionales presentaron una mayor variación, en cuanto a las formas farmacéuticas y mayor porcentaje de formulaciones líquidas investigadas, en comparación con los internacionales. Además de la fuerte dependencia externa para la realización de los ensayos clínicos, se destacó el desafío para el cuidado pediátrico en Brasil, que presenta peculiaridades epidemiológicas en un ambiente propicio al uso de medicamentos sin licencia para niños.

The Quest for Anticancer Vaccines: Deciphering the Fine-Epitope Specificity of Cancer-Related Monoclonal Antibodies by Combining Microarray Screening and Saturation Transfer Difference NMR.

The identification of MUC1 tumor-associated Tn antigen (αGalpNAc1-O-Ser/Thr) has boosted the development of anticancer vaccines. Combining microarrays and saturation transfer difference NMR, we have characterized the fine-epitope mapping of a MUC1 chemical library (naked and Tn-glycosylated) toward two families of cancer-related monoclonal antibodies (anti-MUC1 and anti-Tn mAbs). Anti-MUC1 mAbs clone VU-3C6 and VU-11E2 recognize naked MUC1-derived peptides and bind GalNAc in a peptide-sequence-dependent manner. In contrast, anti-Tn mAbs clone 8D4 and 14D6 mostly recognize the GalNAc and do not bind naked MUC1-derived peptides. These anti-Tn mAbs show a clear preference for glycopeptides containing the Tn-Ser antigen rather than the Tn-Thr analogue, stressing the role of the underlying amino acid (serine or threonine) in the binding process. The reported strategy can be employed, in general, to unveil the key minimal structural features that modulate antigen-antibody recognition, with particular relevance for the development of Tn-MUC1-based anticancer vaccines.

Detection of tumor-associated glycopeptides by lectins: the peptide context modulates carbohydrate recognition.

Tn antigen (α-O-GalNAc-Ser/Thr) is a convenient cancer biomarker that is recognized by antibodies and lectins. This work yields remarkable results for two plant lectins in terms of epitope recognition and reveals that these receptors show higher affinity for Tn antigen when it is incorporated in the Pro-Asp-Thr-Arg (PDTR) peptide region of mucin MUC1. In contrast, a significant affinity loss is observed when Tn antigen is located in the Ala-His-Gly-Val-Thr-Ser-Ala (AHGVTSA) or Ala-Pro-Gly-Ser-Thr-Ala-Pro (APGSTAP) fragments. Our data indicate that the charged residues, Arg and Asp, present in the PDTR sequence establish noteworthy fundamental interactions with the lectin surface as well as fix the conformation of the peptide backbone, favoring the presentation of the sugar moiety toward the lectin. These results may help to better understand glycopeptide-lectin interactions and may contribute to engineer new binding sites, allowing novel glycosensors for Tn antigen detection to be designed.

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.

The human macrophage galactose-type lectin (MGL) is a key physiological receptor for the carcinoma-associated Tn antigen (GalNAc-α-1-O-Ser/Thr) in mucins. NMR and modeling-based data on the molecular recognition features of synthetic Tn-bearing glycopeptides by MGL are presented. Cognate epitopes on the sugar and matching key amino acids involved in the interaction were 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 MGL binding, as is Ca(2+) . NMR data were 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 MGL. 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.

Relações familiares e comportamento alimentar / Family relationship and eating behaviors

Explorou-se a influência das relações familiares no comportamento alimentar das crianças e no desenvolvimento do excesso de peso. Participaram 147 crianças de todas as classes de peso, com idades compreendidas entre os 8 e os 12 anos e respetivas famílias. Às crianças foi aplicada a escala das Relações Familiares do Family Environmemt Scale (FES) e ao principal cuidador o Child Eating Behaviour Questionnaire (CEBQ). Os resultados indicam que o Índice de Massa Corporal (IMC) dos pais é, por si só, um fraco preditor do estatuto de peso dos filhos. Em famílias mais disfuncionais, os filhos têm comportamentos alimentares mais orientados para a atração pela comida, independentemente da classe de peso dos pais.

We explored the influence of family environment, and in particular, the influence of the type of relations established between family members on children's eating behavior and their overweight. A sample of 147 children, with ages between 8 and 12, of all weight classes, completed the Family Relationship subscale of the Family Environmental Scale (FES). Their main caretaker completed the Child Eating Behavior Questionnaire (CEBQ). Parents' Body Mass Index (BMI), by itself, was found to be a weak predictor of children's weight. Family relationship emerged consistently as highly determinant on children's eating behaviors and in families with dysfunctional structures children manifested a greater tendency to behaviors related to attraction to food, regardless of their parent's weight.