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J Tormo

Publications and source records attributed to J Tormo.

32 records · Page 2Linked to original sources
PubMed1994

Crystal structure of a human rhinovirus neutralizing antibody complexed with a peptide derived from viral capsid protein VP2.

The three-dimensional structure of the complex between the Fab fragment of an anti-human rhinovirus neutralizing antibody (8F5) and a cross-reactive synthetic peptide from the viral capsid protein VP2 has been determined at 2.5 A resolution by crystallographic methods. The refinement is presently at an R factor of 0.18 and the antigen-binding site and viral peptide are well defined. The peptide antigen adopts a compact fold by two tight turns and interacts through hydrogen bonds, some with ionic character, and van der Waals contacts with antibody residues from the six hypervariable loops as well as several framework amino acids. The conformation adopted by the peptide is closely related to the corresponding region of the viral protein VP2 on the surface of human rhinovirus 1A whose three-dimensional structure is known. Implications for the cross-reactivity between peptides and the viral capsid are discussed. The peptide-antibody interactions, together with the analysis of mutant viruses that escape neutralization by 8F5 suggest two different mechanisms for viral escape. The comparison between the complexed and uncomplexed antibody structures shows important conformational rearrangements, especially in the hypervariable loops of the heavy chain. Thus, it constitutes a clear example of the 'induced fit' molecular recognition mechanism.

Amino Acid Sequence↗
PubMed1994

Investigation of shape variations in the antibody binding site by molecular dynamics computer simulation.

Molecular dynamics simulations have been used to investigate the flexibility and variations in the shape of the binding site of an antibody against human Rhinovirus serotype 2 (HRV2) and its complex with a 15 amino acid oligopeptide, the structure of which has been recently determined by X-ray crystallography. During the simulation of the unbound antibody the binding site, defined in terms of the hypervariable regions or complementarity determining regions (CDRs), shows significant fluctuations in shape. For the complex such variations in the shape of the binding site were reduced. The largest fluctuations in the unbound antibody occurred within the CDR-H3. The largest differences between the bound and unbound crystal structures are also associated with CDR-H3. The relative displacements of the loops have been analysed in terms of internal distortions, rigid body motions of the loops and changes with respect to the framework regions. The degree to which the motions of the loops are correlated and the variation in the volume of the binding pocket during the simulation have also been examined.

Amino Acid Sequence↗
PubMed1994

Crystallization and preliminary X-ray diffraction studies of a monoclonal antibody Fab fragment against foot-and-mouth disease virus and of its complex with the main antigenic site peptide.

The Fab fragment of the neutralizing monoclonal antibody SD6 elicited against foot-and-mouth disease virus (FMDV) C-S8c1 and its complex with a peptide, corresponding to the major antigenic site of FMDV (VP1 residues 136-150, YTASARGDLAHLTTT), have been crystallized using the hanging drop vapor diffusion techniques. For the isolated Fab, crystals diffracting to 2.5 A resolution were obtained at room temperature using ammonium sulfate as precipitant. These crystals are monoclinic, space group C2, and unit cell parameters a = 109.53 A, b = 89.12 A, c = 64.04 A, and beta = 112.9 degrees and contain one Fab molecule per asymmetric unit. Crystals from the complex diffract, at least, to 2.8 A resolution and were obtained, at room temperature, using PEG as precipitant. These crystals are monoclinic, space group P2, and unit cell parameters a = 56.11 A, b = 60.67 A, c = 143.45 A, and beta = 95.4 degrees. Density packing considerations indicate that there are two Fab molecules in the asymmetric unit.

Amino Acid Sequence↗
PubMed1994

Virulence factors in clinical and food isolates of Aeromonas species.

Virulence factors were compared in 15 Aeromonas spp. isolated from faeces of patients with Aeromonas-associated gastroenteritis and in 81 strains isolated from food. Strains from food did not show differences in the distribution of virulence factors when compared with strains isolated from faeces. However, 88.8% of Aeromonas strains isolated from food were capable of producing possible virulence factors. Characterization of 28 autoagglutinating (AA+) Aeromonas spp. indicated that the human strains differed from the food strains in hemagglutinating and hemolytic capacities. These results suggest that autoagglutination associated with hemagglutinating and hemolytic capacities in food strains may be a helpful indicator of potential pathogenicity.

Acriflavine↗
PubMed1994

Incidence of motile Aeromonas spp. in foods.

A total of 80 food samples were purchased from local retail consumer shops and examined for the presence of motile Aeromonas spp. Of the food categories tested, poultry had the highest incidence, with 100% positive. This was followed by lamb samples, with 60% positive. Raw milk and cheese samples had very low incidence (20%). No motile Aeromonas spp. were found in pre-prepared salads. Shellfish, fish, pork and beef samples had incidences of 40%. Most of the strains isolated were Aeromonas hydrophila, and for most of the food categories, no Aeromonas caviae isolates were obtained.

Aeromonas↗
PubMed1993

[Human papilloma virus in the etiology of cervicouterine cancer].

The objectives of this study were to confirm the hypothesis that invasive carcinoma of the uterine cervix and the precursors of that condition are most often caused by human papilloma virus (HPV) infections, and to determine whether or not other risk factors are involved in the neoplastic process. For this purpose, four concurrent case-control studies were carried out. Two included cases of invasive cervical cancer and population-based controls. The other two included cases of in situ carcinoma and controls. Research was carried out in nine provinces of Spain and in Cali, Colombia. The identification of cases took place between June 1985 and June 1988. The studies included 436 incident cases of invasive carcinoma and 387 controls, selected at random from the corresponding populations, and 525 cases of in situ carcinoma and 512 controls paired by age, place of recruitment, and date that cytological specimens were taken from the women participating in cytological screening programs. Exposure to HPV was detected through hybridization tests after amplification by polymerase chain reaction (PCR) in exfoliated cervical cells from cases and controls. Exposure to HPV was the principal risk factor in the four studies. For invasive carcinoma, the relative risk and 95% confidence interval were 46.2 (18.5-115.1) in Spain and 15.6 (6.9-34.7) in Colombia. For in situ carcinoma, the figures were 56.9 (24.8-130.6) in Spain and 15.5 (8.2-29.4) in Colombia. This strong association was specific for types 16, 18, 31, 33, and 35 as well as still-unclassified HPV types.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma in Situ↗
PubMed1992

Crystal structure of a helical oligopeptide model of polyglycine II and of other polyamides: acetyl-(glycyl-beta-alanyl)2-NH propyl.

We synthesized and solved the crystalline structure of the oligopeptide acetyl-(glycyl-beta-alanyl)2-NH propyl. The crystal is formed by layers of helical molecules with the same chirality; however, right-handed layers alternate with left-handed ones. Inside every layer, the packing of helices is pseudohexagonal with hydrogen bonds between neighbor molecules. The structure found affords direct support for the model proposed by Crick and Rich for polyglycine II and also provides an interpretation for the structure of a newly found family of polyamides that do not form sheets as observed in most nylon structures.

Amino Acid Sequence↗
PubMed1992

Three-dimensional structure of the Fab fragment of a neutralizing antibody to human rhinovirus serotype 2.

The crystal structure of the antigen-binding fragment of a monoclonal antibody (8F5) that neutralizes human rhinovirus serotype 2 has been determined by X-ray diffraction studies. Antibody 8F5, obtained by immunization with native HRV2 virions, cross-reacts with peptides of the viral capsid protein VP2, which contribute to the neutralizing immunogenic site B in this serotype. The structure was solved by the molecular replacement method and has been refined to an R-factor of 18.9% at 2.8 A resolution. The elbow angle, relating the variable and constant modules of the molecule is 127 degrees, representing the smallest elbow angle observed so far in an Fab fragment. Furthermore, the charged residues of the epitope can be well accommodated in the antigen-binding site. This is the first crystal structure reported for an antibody directed against an icosahedral virus.

Amino Acid Sequence↗
PubMed1990

Crystallization and preliminary x-ray diffraction studies of the Fab fragment of a neutralizing monoclonal antibody directed against human rhinovirus serotype 2.

We report on the preparation, crystallization, and preliminary x-ray diffraction analysis of the Fab fragment of the monoclonal antibody 8F5 that neutralizes infectivity of human rhinovirus serotype 2 (HRV2). Fab fragments prepared from this antibody by papain digestion were purified to isoelectric homogeneity by ion exchange chromatography and chromatofocusing. Crystals were obtained by the hanging drop vapor diffusion method using ammonium sulfate as precipitant. The crystals belong to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 59.9 A, b = 86.3 A, c = 128.2 A and diffract to at least 2.8-A resolution. The cell volume suggests the presence of one molecule per asymmetric unit, and the solvent content is estimated to be 61%.

Antibodies, Monoclonal↗
PubMed1990

Crystallization and preliminary X-ray diffraction analysis of catalase HPII from Escherichia coli.

Green crystals of the hexameric catalase HPII from Escherichia coli have been obtained by the hanging-drop method. The crystals belong to the monoclinic space group P2 with a = 123 A, b = 132 A, c = 93 A, beta = 112.5 degrees. There are three subunits in the asymmetric unit. The crystals diffract at least to 3.2 A resolution and are suitable for further X-ray diffraction studies.

Catalase↗
PubMed1990

[Differences by sex in the presentation and follow-up in the first year of acute myocardial infarct].

Three-hundred and nine patients, 242 males and 67 females diagnosed of myocardial infarction were studied during the acute phase and followed for a year to evaluate any differences. The corrected incidence was greater amongst males, 11.1 vs 3.6/10,000 inhabitants. The presenting age was significantly lower in males below 50 and greater in women above 70. Hypertension, hypercholesterolemia and sedentariness were more prevalent amongst women; smoking was more prevalent amongst males. Infarction presentation was typical in both sexes being significant a 5 hour delay in arriving to the hospital in female patients. On hospital admission Killip III-IV was significantly more frequent amongst women (17% vs 4.6%). Hospital mortality although it was higher in women this was not statistically significant (19.4% vs 14.4%). During follow up there was a better control of risk factors in the male patients. Heart failure and mortality were greater amongst women during the first three months (p less than 0.001). Mortality differences continued being statistically significant during the following three months. From the sixth month to the first year, mortality rates were similar. The study suggests that infarction prognosis is worse in females.

Adult↗