Browse
Submit Data
Databases
API
Help

Dataset Information

11 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Structural studies on individual components of bovine transferrin.

ABSTRACT: The single-banding components of bovine transferrin from animals homozygous for the four transferrin variants found in the U.K. were isolated. Sedimentation equilibrium ultracentrifugation and sodium dodecyl sulphate-polyacrylamide-gel electrophoresis showed that the bands of a single variant have molecular weights of 77500 and 73300 respectively. The different bands of a single variant and single bands of different variants show no evidence of size heterogeneity or of low-molecular-weight peptides being split off after reduction in 6m-guanidine hydrochloride. The two slower bands of a single variant, which both contain 2 molecules of sialic acid/molecule of protein, have the same molecular weight and amino acid composition, and give identical peptide ;maps', although differences in composition and peptide ;maps' occur between the different variants. The results support the concept that bovine transferrin is essentially a single polypeptide chain, but they do not explain differences in electrophoretic mobility between bands of the same variant which are not produced by differing sialic acid content.

SUBMITTER: Richardson NE

PROVIDER: S-EPMC1165792 | biostudies-other | 1973 Sep

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Structural studies on bovine -crystallin.

Project description:The amino acid sequences around the cysteine residues in the lens protein, gamma-crystallin, were studied. Fraction II of the gamma-crystallin from calf lens (Björk, 1964) was used. The protein was oxidized with performic acid and then hydrolysed with trypsin. Six peptides containing cysteic acid were isolated. One of the peptides contained three residues of cysteic acid and the others contained one residue of cysteic acid. We conclude that there are eight unique residues of cysteic acid in the oxidized protein. Amino acid analysis suggests that there are also eight residues of cysteic acid in the molecule, which thus contains only one polypeptide chain.

| S-EPMC1176593 | biostudies-other

Structural and functional studies on the stalk of the transferrin receptor.

Project description:Transferrin (Tf) is an iron carrier protein that consists of two lobes, the N- and C-lobes, which can each bind a Fe(3+) ion. Tf binds to its receptor (TfR), which mediates iron delivery to cells through an endocytotic pathway. Receptor binding facilitates iron release from the Tf C-lobe, but impedes iron release from the N-lobe. An atomic model of the Tf-TfR complex based on single particle electron microscopy (EM) indicated that receptor binding is indeed likely to hinder opening of the N-lobe, thus interfering with its iron release. The atomic model also suggested that the TfR stalks could form additional contacts with the Tf N-lobes, thus potentially further slowing down its iron release. Here, we show that the TfR stalks are unlikely to make strong interactions with the Tf N-lobes and that the stalks have no effect on iron release from the N-lobes of receptor-bound Tf.

| S-EPMC2692427 | biostudies-literature

Structural studies on membrane-bound bovine rhodopsin.

Project description:Our previous work has shown that the treatment of bovine rhodopsin with the proteolytic enzyme papain gives rise to a cleaved, but fully functional, complex consisting of three fragments, H, M and L (heavy, medium and light), held together by strong non-covalent forces. By using some of the chemical and physical differences between the three fragments, a protocol for the preparative isolation of each fragment was devised. Purified M-fragment, which had been radiochemically labelled at the retinal-binding site was treated with CNBr and the mixture subjected to a multi-step separation to furnish a retinyl peptide. The sequence analysis of the latter showed that the retinal-binding lysine residue was located at position 296 from the N-terminal of rhodopsin (or residue 53 from the C-terminal). In order to ascertain the position of the cytoplasmic loop which exists between the M- and L-fragments, radiochemically labelled L-fragment was isolated from the cleaved complex. The purified L-fragment was shown to consist of two populations of peptides which were produced by the action of papain on the bonds between Lys-311 and Gln-312 and between Gln-312 and Phe-313.

| S-EPMC1154327 | biostudies-other

Soluble transferrin receptor levels are positively associated with insulin resistance but not with the metabolic syndrome or its individual components.

Project description:The metabolic syndrome (MetS) is known to be associated with elevated serum ferritin levels. The possible association with other Fe markers has been less well studied. We aimed to investigate the cross-sectional association of soluble transferrin receptor (sTfR) and ferritin levels with the MetS components, insulin resistance and glycosylated Hb (HbA1C). The sample consisted of 725 adults, aged 19-93 years (284 men, 151 premenopausal and 290 postmenopausal women), from the Croatian island of Vis. Serum sTfR and ferritin levels were measured by immunoturbidimetry and electrochemiluminescence assays, respectively. The MetS was defined using modified international consensus criteria. Logistic and linear regression analyses were conducted to investigate the associations adjusting for age, fibrinogen, smoking status, alcohol consumption and BMI. Prevalence of the MetS was 48·7 %. Standardised values of ferritin were positively associated with all of the MetS components (except high blood pressure and waist circumference) in men (P0·05). sTfR levels could be spuriously elevated in subjects with insulin resistance and without association with the MetS or its components. We conclude that different markers of Fe metabolism are not consistently associated with cardiometabolic risk.

| S-EPMC5860738 | biostudies-literature

The structural basis of transferrin sequestration by transferrin-binding protein B.

Project description:Neisseria meningitidis, the causative agent of bacterial meningitis, acquires the essential element iron from the host glycoprotein transferrin during infection through a surface transferrin receptor system composed of proteins TbpA and TbpB. Here we present the crystal structures of TbpB from N. meningitidis in its apo form and in complex with human transferrin. The structure reveals how TbpB sequesters and initiates iron release from human transferrin.

| S-EPMC3981719 | biostudies-literature

Structural studies on the glycoproteins from bovine cervical mucus.

Project description:The depolymerization of bovine cervical glycoprotein resulting from cleavage of disulphide bonds. Pronase digestion and both procedures sequentially was assessed by using gel filtration. Cleavage of disulphide bonds followed by Pronase digestion produced more extensive depolymerization than did either treatment alone, and gel filtration of the products resulted in two major peaks of glycosylated material on Sepharose CL-2B and Sepharose 4B. The glycopolypeptides in both peaks had similar sugar and sulphate compositions, but they migrated to different extents on gel electrophoresis. Electrophoretic studies indicated that both glycopolypeptides were derived from the same glycoprotein molecule and not from a mixture of two similar glycoproteins. Pronase digestion of glycoproteins in which the disulphide bonds had been labelled with iodo-[1-14C]acetamide revealed that most of the cysteine residues were situated in regions susceptible to Pronase. The results show the presence of two types of structural regions in bovine cervical glycoprotein, namely 'naked' peptide or non-glycosylated regions and glycopolypeptide subunit regions in which glycopolypeptides of two different sizes predominate. Comparison of the cervical glycoproteins isolated from mucus secreted during oestrus and pregnancy, by the methods outlined above, did not reveal any structural differences in the glycoproteins to explain the different physical properties of the mucus secreted under these conditions.

| S-EPMC1185863 | biostudies-other

Structural variations within the transferrin binding site on transferrin-binding protein B, TbpB.

Project description:Pathogenic bacteria acquire the essential element iron through specialized uptake pathways that are necessary in the iron-limiting environments of the host. Members of the Gram-negative Neisseriaceae and Pasteurellaceae families have adapted to acquire iron from the host iron binding glycoprotein, transferrin (Tf), through a receptor complex comprised of transferring-binding protein (Tbp) A and B. Because of the critical role they play in the host, these surface-exposed proteins are invariably present in clinical isolates and thus are considered prime vaccine targets. The specific interactions between TbpB and Tf are essential and ultimately might be exploited to create a broad-spectrum vaccine. In this study, we report the structure of TbpBs from two porcine pathogens, Actinobacillus pleuropneumoniae and suis. Paradoxically, despite a common Tf target, these swine related TbpBs show substantial sequence variation in their Tf-binding site. The TbpB structures, supported by docking simulations, surface plasmon resonance and hydrogen/deuterium exchange experiments with wild-type and mutant TbpBs, explain why there are structurally conserved elements within TbpB homologs despite major sequence variation that are required for binding Tf.

| S-EPMC3069468 | biostudies-literature

Alzheimer's disease diagnosis in individual subjects using structural MR images: validation studies.

Project description:ObjectiveTo develop and validate a tool for Alzheimer's disease (AD) diagnosis in individual subjects using support vector machine (SVM)-based classification of structural MR (sMR) images.BackgroundLibraries of sMR scans of clinically well characterized subjects can be harnessed for the purpose of diagnosing new incoming subjects.MethodsOne hundred ninety patients with probable AD were age- and gender-matched with 190 cognitively normal (CN) subjects. Three different classification models were implemented: Model I uses tissue densities obtained from sMR scans to give STructural Abnormality iNDex (STAND)-score; and Models II and III use tissue densities as well as covariates (demographics and Apolipoprotein E genotype) to give adjusted-STAND (aSTAND)-score. Data from 140 AD and 140 CN were used for training. The SVM parameter optimization and training were done by four-fold cross validation (CV). The remaining independent sample of 50 AD and 50 CN was used to obtain a minimally biased estimate of the generalization error of the algorithm.ResultsThe CV accuracy of Model II and Model III aSTAND-scores was 88.5% and 89.3%, respectively, and the developed models generalized well on the independent test data sets. Anatomic patterns best differentiating the groups were consistent with the known distribution of neurofibrillary AD pathology.ConclusionsThis paper presents preliminary evidence that application of SVM-based classification of an individual sMR scan relative to a library of scans can provide useful information in individual subjects for diagnosis of AD. Including demographic and genetic information in the classification algorithm slightly improves diagnostic accuracy.

| S-EPMC2390889 | biostudies-literature

Characterization of a novel transferrin receptor in bovine strains of Pasteurella multocida.

Project description:Analysis of bovine respiratory isolates of Pasteurella multocida demonstrated that six of nine strains tested were capable of growth dependent upon bovine transferrin and of specifically binding ruminant transferrins. A single 82-kDa protein was affinity isolated from the P. multocida strains with immobilized bovine transferrin. In contrast to what has been observed in other species, binding of this protein to immobilized transferrin was specifically blocked by the N-lobe subfragment of bovine transferrin. A single gene encoding the 82-kDa protein was flanked by a leucyl-tRNA synthetase gene and an IS1060 element, in contrast to other species where genes encoding the two receptor proteins (TbpB and TbpA) are found in an operonic arrangement. A similar gene arrangement was observed in all of the receptor-positive strains, in spite of the observation that they belonged to different genomic groups. Analysis of the deduced amino acid sequence of the receptor protein indicated that it is a member of the TonB-dependent outer membrane receptor family, and although it is related to transferrin and lactoferrin receptor proteins (TbpAs and LbpAs) from other species, it differs substantially from other members of this group. Amino acid alignments suggest that the reduced size (20 kDa smaller) of the P. multocida TbpA is primarily due to the absence of larger predicted external loops. Collectively these results suggest that P. multocida has a single, novel receptor protein (TbpA) that is capable of efficiently mediating iron acquisition from bovine transferrin without the involvement of a second receptor protein (TbpB).

| S-EPMC94955 | biostudies-literature

Structural and immunological studies of keratan sulphates from mature bovine articular cartilage.

Project description:Two populations of alkaline-borohydride-reduced keratan sulphate (KS) chains were prepared from the two peptido-keratan sulphate trypsin fragments of proteoglycan aggregates isolated from bovine femoral head cartilage (6-year-old animals). Each population was separated by high-performance ion-exchange chromatography on a Pharmacia Mono-Q column into eight pools, Q1-Q8. These were analysed by gel permeation chromatography, radioimmunoassay with the monoclonal antibody MZ15, and 500 MHz 1H n.m.r. spectroscopy. Upon chromatography on Sephadex G-75 the Mono-Q fractions were shown to increase in hydrodynamic size progressively from Q1 to Q8 for both KS populations. For each population the strongest antigenic response with the anti-KS monoclonal antibody MZ15 was expressed by the two fractions of greatest size and charge density, Q7 and Q8. Proton n.m.r. spectroscopic studies on the two series of fractions demonstrated: (i) a progressive increase in the level of galactose sulphation from Q1 to Q8, (ii) the presence of approximately one alpha(1-3)-linked fucose residue per chain in every sample, and (iii) the presence of N-acetylneuraminic acids in three discrete environments, two alpha(2-3)- and one alpha(2-6)-linked in every sample. The results are discussed in terms of a possible heterogeneity in the carbohydrate-protein linkage region of keratan sulphates from bovine articular cartilage.

| S-EPMC1138657 | biostudies-other

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data