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G Wagner

Publications and source records attributed to G Wagner.

At least 271 records · Page 15Linked to original sources
PubMed1993

The CD58 (LFA-3) binding site is a localized and highly charged surface area on the AGFCC'C" face of the human CD2 adhesion domain.

Using site-directed mutagenesis in conjunction with NMR structural data on the adhesion domain of human CD2, we have defined the binding region for CD58. Previous structural studies of rat and human CD2 indicate that this adhesion domain is immunoglobulin-like. Here we report that the CD58 binding site is a well-circumscribed, charged surface area covering approximately 770 A2 on the AGFCC'C" face of the CD2 beta barrel. This site contains beta-strand residues in the carboxyl-terminal half of the F strand (including Lys-82 and Tyr-86), the top of the C strand (Asp-32 and Lys-34), and the C' strand (Gln-46), which are all solvent exposed. In addition, several exposed residues on the FG loop (Gly-90, Lys-91, Asn-92, and Val-93), the CC' loop (Lys-41 and Lys-43), and the C'C" loop (Arg-48 and Lys-51) form this site. In contrast, neither residues on the more peripheral G and C" strands of the same CD2 surface nor residues on B, E, and D strands of the opposite face are involved in CD58 binding. This CD58 binding site is predicted to lie most distal to the T-lymphocyte surface membrane, with ready access to CD58 on the surface of the opposing antigen-presenting cell.

Amino Acid Sequence↗
PubMed1993

1H resonance assignments and secondary structure of the 13.6 kDa glycosylated adhesion domain of human CD2.

Human CD2, a glycosylated transmembrane receptor found on all T-lymphocytes, plays a key role in facilitating cellular adhesion between T-cells and target cells or antigen-presenting cells by binding to its counter receptor CD58 (LFA-3) present on the surface of those cells. All CD2 adhesion functions are localized within the amino-terminal 105-residue domain, which contains a single high mannose N-glycan required for maintaining both the conformational stability and CD58 binding properties of the glycoprotein. In order to better understand the structural basis for CD2-CD58-mediated adhesion and the critical role of the carbohydrate moiety in maintaining the functional stability of the molecule, we have determined the secondary structure of the N-glycosylated adhesion domain of human CD2 (hu-sCD2(105)) using NMR spectroscopy. Most of the 1H resonance assignments have been obtained from 1H-1H homonuclear 2D NMR spectra, which were further extended by applying 1H-15N heteronuclear 2D experiments on a hu-sCD2(105) sample selectively labeled with [15N]lysine. Thus, 98% of all backbone 1H resonances and over 80% of all side chain 1H resonances have been assigned. An overall topology characteristic of an immunoglobulin variable domain is observed, which consists of two beta-sheets comprised of three (residues 16-20, 67-71, and 60-63) and five (residues 94-103, 80-86, 32-37, 45-47, and 53-55) antiparallel beta-strands, respectively, with a hydrophobic core sandwiched between them. A ninth beta-strand (residues 7-12) makes parallel contacts to the carboxy-terminal beta-strand. NOEs between the N-linked glycan and the protein have tentatively been identified.

Amino Acid Sequence↗
PubMed1993

Structure of the glycosylated adhesion domain of human T lymphocyte glycoprotein CD2.

BACKGROUND: CD2, a T-cell specific surface glycoprotein, is critically important for mediating adherence of T cells to antigen-presenting cells or target cells. Domain 1 of human CD2 is responsible for cell adhesion, binding to CD58 (LFA-3) expressed on the cell to which the T cell binds. Human CD2 domain 1 requires N-linked carbohydrate to maintain its native conformation and ability to bind CD58. In contrast, rat CD2 does not require N-linked carbohydrate, and binds to a different ligand, CD48. RESULTS: The three-dimensional structure of the glycosylated form of domain 1 of human CD2 has been determined by NMR spectroscopy. The overall structure resembles the typical beta-barrel of an immunoglobulin variable domain. Nuclear Overhauser enhancement contacts between the protein and the N-linked glycan have been tentatively identified. CONCLUSION: Based on our results, we propose a model showing how the N-linked glycan might be positioned in the human CD2 domain 1 structure. The model provides an explanation for the observed instability of deglycosylated human CD2, and allows residues that are important for CD58 binding to be differentiated from those affecting conformational stability via interactions with the glycan.

Amino Acid Sequence↗
PubMed1993

Repair of DNA methylphosphotriesters through a metalloactivated cysteine nucleophile.

The Escherichia coli Ada protein repairs methylphosphotriesters in DNA by direct, irreversible methyl transfer to one of its own cysteines. Upon methyl transfer, Ada acquires the ability to bind specific DNA sequences and thereby to induce genes that confer resistance to methylating agents. The amino-terminal domain of Ada, which comprises the methylphosphotriester repair and sequence-specific DNA binding elements, contains a tightly bound zinc ion. Analysis of the zinc binding site by cadmium-113 nuclear magnetic resonance and site-directed mutagenesis revealed that zinc participates in the autocatalytic activation of the active site cysteine and may also function as a conformational switch.

Bacterial Proteins↗
PubMed1993

Secondary structure and backbone resonance assignments of the periplasmic cyclophilin type peptidyl-prolyl isomerase from Escherichia coli.

Proton, carbon-13, and nitrogen-15 sequence-specific backbone assignments have been obtained for the periplasmic cyclophilin type cis-trans peptidyl-prolyl isomerase from Escherichia coli (167 residues, M(r) = 18,244). Assignments were obtained using both 1H, 13C, and 15N triple-resonance and 1H and 15N double-resonance three-dimensional (3D) NMR spectroscopy at pH 6.2, 25 degrees C. Complete or partial residue-specific assignments have been obtained for 165 of the 167 residues. The secondary structure has been characterized using long- and medium-range NOEs. The protein consists of an eight-stranded anti-parallel beta-sheet and two helices. The overall topology of E. coli cyclophilin is similar to that of human T-cell cyclophilin. Sequence alignment with human T-cell cyclophilin based on secondary structure homology implicates several residues in E. coli cyclophilin that may be crucial for binding the peptide substrate AC-A-A-P-A-AMC and the immunosuppressive drug cyclosporin A.

Amino Acid Isomerases↗
PubMed1993

Cysteine pairing in the glycoprotein IIbIIIa antagonist kistrin using NMR, chemical analysis, and structure calculations.

The pairing of the cysteines in disulfide bonds was investigated for the 68-residue RGD-containing protein kistrin, a potent antagonist of the integrin GP IIbIIIa and an inhibitor of platelet aggregation. Kistrin belongs to a family of homologous proteins found in snake venoms termed disintegrins, all of which have a cysteine content. The disulfide pairing of the 12 cysteines was investigated by chemical analysis, NMR spectroscopy, and distance geometry calculations. The data show that the disulfide pairs are 4-19, 6-14, 13-36, 27-33, 32-57, and 45-64. The various means for assigning the disulfide bonds are described, and the results are compared with the cysteine pairings reported for other disintegrin proteins.

Amino Acid Sequence↗
PubMed1993

Application of nonlinear sampling schemes to COSY-type spectra.

Nonlinear sampling along the t1 dimension is applied to COSY-type spectra. The sine dependence of the time domain signals for the cross peaks is matched by a nonlinear sampling scheme that samples most densely around the maximum of the sine function. Data are processed by maximum entropy reconstruction, using a modified implementation of the 'Cambridge' algorithm of Skilling and Bryan. The procedure is demonstrated for P.E. COSY spectra recorded on a cyclic hexapeptide and on a 126-residue domain of the protein villin. The number of t1 values in the nonlinearly sampled experiments was reduced by a factor of four compared to linear sampling. The sensitivity and resolution of the resulting spectra are comparable to those achieved by conventional methods. The method described can thus significantly reduce the measuring time for COSY-type spectra.

Algorithms↗
PubMed1993

Prospects for NMR of large proteins.

During the last decade, solution structures of many small proteins have been solved by NMR. The size of proteins that are being analyzed by NMR seems to increase steadily. Protein structures up to 18 kD have been solved so far, and spectra of proteins up to 30 kD have been assigned. Thus, NMR emerges as an attractive technique, in particular for structural studies of proteins that cannot by crystallized. However, the application of the technology is limited by relaxation properties of the proteins. If relaxation would only be determined by Stokes-Einstein-type rotational diffusion, the effects of the molecular size on relaxation properties of proteins and thus on the performance of multi-dimensional multiple-resonance experiments could readily be estimated. From this perspective, solving two- or three-fold larger structures seems possible. However, most larger proteins exhibit serious line broadening due to aggregation or other still unknown effects. Sample conditioning to minimize these effects is presently the challenge in the work with large proteins.

Magnetic Resonance Spectroscopy↗
PubMed1993

Simultaneous active and passive immunization against hepatitis A studied in a population of travellers.

Three hundred travellers, seronegative for hepatitis A, were enrolled into this study to evaluate a new inactivated hepatitis A vaccine. Three injections, each containing at least 720 ELISA units, were administered intramuscularly at months 0, 1 and 6. The subjects were distributed into three groups: 100 received vaccine only; 100 received a single injection of immunoglobulin enriched in HAV antibody; and the 100 remaining travellers received the vaccine and immunoglobulin administered simultaneously with the first vaccine dose. In both vaccinated groups, the rate of seroconversion was found to be higher than 90% at month 1, reaching 100% and 97.8% at month 2 in groups 1 and 3, respectively, and 100% at month 7. In the group receiving both vaccine and immunoglobulin, antibody production was somewhat slower and the final titres were, on average, slightly lower than those obtained in the group with the vaccine alone (GMT 2488 and 3614 mIU ml-1 respectively; p = 0.02). The vaccine appeared to be highly immunogenic in all subjects and was also well tolerated. The slight inhibition of antibody production, induced by the concurrent administration of immunoglobulin, does not affect the overall protection afforded by the vaccine. We conclude that simultaneous active and passive hepatitis A immunizations can be recommended.

Adolescent↗
PubMed1993

Differential effects of first antiepileptic drug application on cognition in lesional and non-lesional patients with epilepsy.

It has been shown that carbamazepine (CBZ) and valproic acid (VPA) have no significant negative or even positive side effects upon cognition in patients with epilepsy. The present study evaluated cognitive effects of CBZ or VPA in 16 patients with newly diagnosed epilepsy. Twelve patients had complex partial seizures, four patients primarily generalized seizures. Special attention was directed towards seizure type, presence of structural lesions and seizure control. Neuropsychological testing was carried out prior to medication and when drugs were within therapeutic ranges. Nineteen untreated healthy subjects served as controls. The following results were obtained: first of all, no general effect of antiepileptic drugs upon cognition could be detected. Only a subgroup with lesion (n = 8) and pre-existing cognitive deficits showed a significant decrease in memory performance during medication. This group additionally obtained poor seizure control. In conclusion, adverse cognitive changes under medication cannot be explained by antiepileptic drugs alone. The presence of cerebral lesions and obtained seizure control have to be considered as essential risk factors.

Attention↗
PubMed1993

Test driving Iowa's FDDI superhighway.

Iowans soon will communicate in a new light: the Iowa Communications Network is a statewide fiber optic network that can change education, and hopefully healthcare, in the state. Users at five Iowa hospitals will enjoy direct access to the ICN because of their affiliated School of Nursing programs. Preparations at Iowa Methodist Medical Center for educational programming over the ICN will put most of the components in place that will be used during a July 22, 1993, demonstration.

Computer Communication Networks↗
PubMed1993

[Personality markers in patients with Sudeck's disease. A psychoanalytic study].

We examined 22 patients suffering from reflex sympathetic dystrophy with psychoanalytic interviews. In all 22 patients we found a common psychological structure corresponding to Balint's basic fault (Balint, 1970). For people with this structure the accident that preceded the reflex sympathetic dystrophy and the following pain, immobilisation and need to help are promoting the patient's regression in a specific way ending in the developing of reflex sympathetic dystrophy. The dispair of the patients about their reflex sympathetic dystrophy expresses unsolved fears of early childhood.

Adult↗
PubMed1993

[Synthesis of 4-methyl-6-phenyl-thieno(2,3-d)pyrimidines with a formamidino- or oxalamidocarbonic acid residue with antianaphylactic activity].

3-Amino-4-methyl-6-phenyl-thieno[2,3-d]pyrimidine-2-carbonic acid alkylesters 1a, b were hydrolyzed to the potassium salt of the carbonic acid 2. Cyclization of 2 with acetanhydride yielded the tricyclic 1,3-oxazinone derivative 4. This compound reacted with pyrrolidine by different conditions of reaction to give the bisamide 7, the acetamidino carbonic acid 5 and their decarboxylated product 6. Compound 1a yielded with Vilsmeier reagents the formamidino compound 3. 3-Amino-thieno[2,3-d]pyrimidin-2-carbonitrile gave under different conditions of reaction with oxalic acid diethylester or with oxalic acid ethylester chloride the tetracyclic 4-methoxy-9-methyl-7-phenyl-thieno[2,3-d:4,5-d']dipyrimidine-2-car bonic acid methylester 10 or the N-(2-cyano-4-methyl-6-phenyl-thieno[2,3-d]pyrimid-3-yl)oxalamid ic ethylester 12. These compounds were hydrolyzed to give the carbonic acids 11 and 13. Some of the synthesized substances showed an antianaphylactic activity.

Anaphylaxis↗
PubMed1993

[Causes of losses in a pig fattening facility].

Losses of fatteners in a pig-husbandry were monitored over a one year period. All fatteners which perished or were slaughtered prematurely were taken into consideration. Out of 10,485 fatteners six hundred (5.7%) pigs were lost prematurely. Of these animals, 360 (60.0%) were slaughtered, and 240 (40.0%) died. Diseases of the respiratory system were the most frequent drop-out reason (32.3%). Pneumonia (mostly pleuropneumonia) was diagnosed in 90.7% of these animals. Thirty one percent of the lost fatteners had diseases of the locomotor system. Of these disorders, 73.1% affected the skeleton and joints, and in 26.9% PSE-syndrome was found. Other disorders were: diseases of the cardiovascular system (13.7%), intestinal tract (10.0%), urogenital tract (1.2%), skin (1.5%), and diseases of other specific organs (5.7%). Cannibalism was found in 2.3% of the lost fatteners, unthriftiness in 1.0%, and in 1.3% the cause of the loss could not be identified. The greatest numbers of fatteners were removed during the cold season, particularly in September. Most of the lost pigs (53.3%) had a body mass between 31 and 60 kg. The highest drop-out rates were found during weeks 2 to 6 and 9 to 12 of the fattening period.

Animals↗
PubMed1993

[Synthesis of furo(2,3-b)pyridine amidines with antianaphylactic activity].

The synthesis of furo[2,3-b]pyridine formamidines (D/1-D/11, F) was realized by the reaction of the 3-amino-furo[2,3-b]pyridines C/1-C/11 and E, substituted in position 2 with a carbonyl moiety with dimethylformamide/phosphoroxide chloride or with N-formyl-piperidine or N-formyl-morpholine and phosphoroxide chloride. The acetamidines H were yielded from 4-oxo-4H-3-methyl-pyrido[3',2':4,5]furo[3,2-d]1,3-oxazines with aminoethanol. The 4-oxo-4H-3-amino-3,4-dihydro-pyrido[3',2':4,5]furo[3,2-d]pyrimidines K and M reacted with dimethylformamide/phosphoroxide chloride to give the tricyclic formamidines L and K. The described amidines showed antianaphylactic activity.

Amidines↗
PubMed1993

[Synthesis of thieno(2,3-b)pyridines with oxalamidic acid or an oxalamidic alkylester residues and of 4-alkoxy-pyrido(3',2':4,5)thieno(3,2-d)pyridine-2-carboxylic acid derivates].

N-(2-Alkoxycarbonyl-thieno[2,3-b]pyrid-3-yl)oxalamide acid alkylester B were synthesized by the reaction of 3-amino-2-carboxylic esters A with oxalic acid diethylester in presence of sodium alkoxides. The 3-amino-2-cyano-thieno[2,3-b]pyridines C yielded under the same conditions via the N-(2-cyano-thieno[2,3-b]pyrid-3-yl)oxalamidic acid alkylesters D/1-D/4 the 4-alkoxy-pyrido[3',2':4,5]thieno[3,2-d]pyrimidine-2-carboxylic acid alkylesters E/1-E/8. The compounds D/1, D/2 and E/1-E/5 were hydrolyzed to give the corresponding carboxylic acids. The 3-amino-furo[2,3-b]pyridine-2-carboxylic acid ethylester H reacted with oxalic ethylester chloride to give the oxalamide ethylester I. The synthesized substances showed an antinaphylactic activity.

Animals↗
PubMed1993

[Synthesis of new pyrido-(3',2':4,5)-thieno-(3,2-d)-1,2,3-triazine derivatives as antianaphylactics].

Some new pyrido[3',2':4,5]thieno[3,2-d]1,2,3-triazine-4(3H)-ones (C) were synthesized from 2-thioxo-1,2-dihydro-3-carbonitriles (A) via the 3-amino-thieno[2,3-b]pyridine-2-carboxamides (B). Substances of structure A were converted to 3-amino-thieno[2,3-b]pyridine-2-carbonitriles (G) which yielded the desired 4-amino substituted compounds I via the tricyclic 4-chloro-pyrido[3',2':4:5]thieno[3,2-d]1,2,3-triazines (H) by the reaction with N-nucleophiles. Some of the investigated compounds showed a respectable antianaphylactic activity.

Animals↗