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78 records – page 1 of 8.

The 1.9 A crystal structure of heat-labile shrimp alkaline phosphatase.

https://arctichealth.org/en/permalink/ahliterature189601
Source
J Mol Biol. 2002 May 17;318(5):1265-74
Publication Type
Article
Date
May-17-2002
Author
Maaike de Backer
Sean McSweeney
Hanne B Rasmussen
Bjørn W Riise
Peter Lindley
Edward Hough
Author Affiliation
European Synchrotron Radiation Facility, Grenoble, France.
Source
J Mol Biol. 2002 May 17;318(5):1265-74
Date
May-17-2002
Language
English
Publication Type
Article
Keywords
Alkaline Phosphatase - chemistry
Animals
Crystallography, X-Ray
Decapoda (Crustacea) - chemistry - enzymology
Humans
Models, Molecular
Protein Conformation
Temperature
Abstract
Alkaline phosphatases are non-specific phosphomonoesterases that are distributed widely in species ranging from bacteria to man. This study has concentrated on the tissue-nonspecific alkaline phosphatase from arctic shrimps (shrimp alkaline phosphatase, SAP). Originating from a cold-active species, SAP is thermolabile and is used widely in vitro, e.g. to dephosphorylate DNA or dNTPs, since it can be inactivated by a short rise in temperature. Since alkaline phosphatases are zinc-containing enzymes, a multiwavelength anomalous dispersion (MAD) experiment was performed on the zinc K edge, which led to the determination of the structure to a resolution of 1.9 A. Anomalous data clearly showed the presence of a zinc triad in the active site, whereas alkaline phosphatases usually contain two zinc and one magnesium ion per monomer. SAP shares the core, an extended beta-sheet flanked by alpha-helices, and a metal triad with the currently known alkaline phosphatase structures (Escherichia coli structures and a human placental structure). Although SAP lacks some features specific for the mammalian enzyme, their backbones are very similar and may therefore be typical for other higher organisms. Furthermore, SAP possesses a striking feature that the other structures lack: surface potential representations show that the enzyme's net charge of -80 is distributed such that the surface is predominantly negatively charged, except for the positively charged active site. The negatively charged substrate must therefore be directed strongly towards the active site. It is generally accepted that optimization of the electrostatics is one of the characteristics related to cold-adaptation. SAP demonstrates this principle very clearly.
PubMed ID
12083516 View in PubMed
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Adsorption inhibition as a mechanism of freezing resistance in polar fishes.

https://arctichealth.org/en/permalink/ahliterature46812
Source
Proc Natl Acad Sci U S A. 1977 Jun;74(6):2589-93
Publication Type
Article
Date
Jun-1977
Author
J A Raymond
A L DeVries
Source
Proc Natl Acad Sci U S A. 1977 Jun;74(6):2589-93
Date
Jun-1977
Language
English
Publication Type
Article
Keywords
Acclimatization
Adsorption
Animals
Blood Proteins - physiology
Cold Climate
Fishes - physiology
Freezing
Glycoproteins - blood
Kinetics
Microscopy, Electron, Scanning
Molecular Weight
Protein Conformation
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Species Specificity
Abstract
Polar fishes are known to have serum proteins and glycoproteins that protect them from freezing, by a noncolligative process. Measurements of antifreeze concentrations in ice and scanning electron micrographs of freeze-dried antifreeze solutions indicate that the antifreezes are incorporated in ice during freezing. The antifreezes also have a pronounced effect on the crystal habit of ice grown in their presence. Each of four antifreezes investigated caused ice to grow in long needles whose axes were parallel to the ice c axis. Together these results indicate the antifreezes adsorb to ice surfaces and inhibit their growth. A model in which adsorbed antifreezes raise the curvature of growth steps on the ice surface is proposed to account for the observed depression of the temperature at which freezing occurs and agrees well with experimental observations. The model is similar to one previously proposed for other cases of crystal growth inhibition.
PubMed ID
267952 View in PubMed
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[Alpha 2-macroglobulin: structure, properties and physiological role]

https://arctichealth.org/en/permalink/ahliterature26949
Source
Ukr Biokhim Zh. 1983 Mar-Apr;55(2):218-33
Publication Type
Article
Author
K N Veremeenko
O S Semeniuta
A I Kizim
K A Lobunets
Source
Ukr Biokhim Zh. 1983 Mar-Apr;55(2):218-33
Language
Ukrainian
Publication Type
Article
Keywords
Amino Acid Sequence
Animals
Blood Protein Electrophoresis
Carbohydrates - analysis
Diagnosis, Differential
English Abstract
Hepatitis, Viral, Human - blood
Humans
Neoplasms - blood
Protease Inhibitors
Protein Conformation
Radiation Injuries, Experimental - drug therapy
Rats
Substrate Specificity
alpha-Macroglobulins - analysis - physiology - therapeutic use
Abstract
The paper is concerned with the results of recent researches devoted to studies of the structure, properties and physiological role of alpha 2-macroglobulin, one of main inhibitors of blood proteolytic enzymes. Data are presented on its primary and quaternary structure, mechanisms of interaction with proteinases. The role of alpha 2-macroglobulin in regulation of the activity of proteinases participating in blood coagulation, fibrinolysis, kininogenesis, immune reactions is shown. Possibilities of its application in medicine are discussed.
PubMed ID
6189273 View in PubMed
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Alpha-methylacyl-CoA racemase from Mycobacterium tuberculosis. Mutational and structural characterization of the active site and the fold.

https://arctichealth.org/en/permalink/ahliterature69307
Source
J Biol Chem. 2005 Apr 1;280(13):12611-20
Publication Type
Article
Date
Apr-1-2005
Author
Kalle Savolainen
Prasenjit Bhaumik
Werner Schmitz
Tiina J Kotti
Ernst Conzelmann
Rik K Wierenga
J Kalervo Hiltunen
Author Affiliation
Biocenter Oulu and Department of Biochemistry, University of Oulu, Linnanmaa, P. O. Box 3000, FIN-90014 University of Oulu, Finland.
Source
J Biol Chem. 2005 Apr 1;280(13):12611-20
Date
Apr-1-2005
Language
English
Publication Type
Article
Keywords
Alanine - chemistry
Amino Acid Sequence
Animals
Bile Acids and Salts - metabolism
Binding Sites
Catalysis
Circular Dichroism
Cloning, Molecular
Crystallography, X-Ray
Dimerization
Escherichia coli - metabolism
Models, Chemical
Models, Molecular
Molecular Sequence Data
Mutation
Mycobacterium tuberculosis - enzymology - genetics
Protein Conformation
Protein Folding
Protein Structure, Secondary
Racemases and Epimerases - chemistry - genetics
Rats
Research Support, Non-U.S. Gov't
Sequence Homology, Amino Acid
Substrate Specificity
Ultraviolet Rays
Abstract
Alpha-methylacyl-CoA racemase (Amacr) catalyzes the racemization of alpha-methyl-branched CoA esters. Sequence comparisons have shown that this enzyme is a member of the family III CoA transferases. The mammalian Amacr is involved in bile acid synthesis and branched-chain fatty acid degradation. In human, mutated variants of Amacr have been shown to be associated with disease states. Amino acid sequence alignment of Amacrs and its homologues from various species revealed 26 conserved protic residues, assumed to be potential candidates as catalytic residues. Amacr from Mycobacterium tuberculosis (MCR) was taken as a representative of the racemases. To determine their importance for efficient catalysis, each of these 26 protic residues of MCR was mutated into an alanine, respectively, and the mutated variants were overexpressed in Escherichia coli. It was found that four variants (R91A, H126A, D156A, and E241A) were properly folded but had much decreased catalytic efficiency. Apparently, Arg91, His126, Asp156, and Glu241 are important catalytic residues of MCR. The importance of these residues for catalysis can be rationalized by the 1.8 A resolution crystal structure of MCR, which shows that the catalytic site is at the interface between the large and small domain of two different subunits of the dimeric enzyme. This crystal structure is the first structure of a complete enzyme of the bile acid synthesis pathway. It shows that MCR has unique structural features, not seen in the structures of the sequence related formyl-CoA transferases, suggesting that the family III CoA transferases can be subdivided in at least two classes, being racemases and CoA transferases.
PubMed ID
15632186 View in PubMed
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Analysis of antibody markers, DRB1, DRB5, DQA1 and DQB1 genes and modeling of DR2 molecules in DR2-positive patients with insulin-dependent diabetes mellitus.

https://arctichealth.org/en/permalink/ahliterature35717
Source
Tissue Antigens. 1994 Aug;44(2):110-9
Publication Type
Article
Date
Aug-1994
Author
C B Sanjeevi
T P Lybrand
M. Landin-Olsson
I. Kockum
G. Dahlquist
W A Hagopian
J P Palmer
A. Lernmark
Author Affiliation
Karolinska Institute, Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden.
Source
Tissue Antigens. 1994 Aug;44(2):110-9
Date
Aug-1994
Language
English
Publication Type
Article
Keywords
Alleles
Animals
Antibodies, Monoclonal - immunology
Base Sequence
Cricetinae
Diabetes Mellitus, Type 1 - genetics - immunology
Disease Susceptibility - immunology
Genes, MHC Class II
Genetic Predisposition to Disease
HLA-DQ Antigens - genetics
HLA-DR Antigens - genetics
HLA-DR2 Antigen - chemistry - genetics
Haplotypes - genetics
Humans
Immunity, Natural - genetics - immunology
Models, Molecular
Molecular Sequence Data
Polymerase Chain Reaction
Polymorphism, Restriction Fragment Length
Protein Conformation
Recombination, Genetic
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Sweden
Abstract
HLA-DR2 is negatively associated with insulin-dependent diabetes mellitus (IDDM). The aim of the present study was to analyze DR2-positive patients among 425 consecutively diagnosed unrelated Swedish children with IDDM and in 367 matched controls. HLA-DRB, -DQA and -DQB were determined by Taq I restriction fragment length polymorphism analysis. Amplification by polymerase chain reaction (PCR) and hybridization with sequence-specific oligonucleotide probes was done for DQA1, DQB1 and DRB1 and DRB5. DR2 was positive in 11/425 patients (3%) and 101/367 (28%) controls (OR 0.07, p
PubMed ID
7817375 View in PubMed
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Androgen-sensitive human prostate cancer cells, LNCaP, produce both N-terminally mature and truncated prostate-specific antigen isoforms.

https://arctichealth.org/en/permalink/ahliterature21491
Source
Eur J Biochem. 1998 Jul 15;255(2):329-35
Publication Type
Article
Date
Jul-15-1998
Author
A. Herrala
R. Kurkela
M. Vihinen
N. Kalkkinen
P. Vihko
Author Affiliation
Biocenter Oulu and WHO Collaborating Centre for Research on Reproductive Health, University of Oulu, Finland.
Source
Eur J Biochem. 1998 Jul 15;255(2):329-35
Date
Jul-15-1998
Language
English
Publication Type
Article
Keywords
Amino Acid Sequence
Computer Graphics
Gene Expression Regulation, Neoplastic - drug effects
Humans
Male
Metribolone - pharmacology
Models, Molecular
Molecular Weight
Peptide Fragments - chemistry
Prostate-Specific Antigen - biosynthesis - chemistry - isolation & purification
Prostatic Neoplasms - metabolism
Protein Conformation
Recombinant Proteins - biosynthesis - chemistry - isolation & purification
Research Support, Non-U.S. Gov't
Semen - chemistry
Testosterone Congeners - pharmacology
Tumor Cells, Cultured
Abstract
To characterize prostate-specific antigen (PSA) produced by cancer cells, different isoforms of PSA secreted by the human prostate cancer cells, LNCaP, were purified. LNCaP-PSA production was induced by synthetic androgen, R1881. LNCaP-PSA was separated into four pools. The molecular mass of LNCaP-PSA isoforms in these pools was 34 kDa under reducing conditions and 29 kDa under nonreducing conditions on SDS/PAGE. pI of LNCaP-PSA isoforms varied from 6.8 to 8.2. Pool A had the highest specific activity, 37 nmol/(min x mg). All the pools formed stable complexes with alpha1-antichymotrypsin and alpha2-macroglobulin. The pools contained 10-60% of N-terminally correctly processed LNCaP-PSA isoforms. According to the molecular modelling, the addition or deletion of two or four N-terminal amino acids could affect the three-dimensional structure and thereby remarkably reduce the enzyme activity of LNCaP-PSA.
PubMed ID
9716373 View in PubMed
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Antigenic characteristics and cDNA sequences of HLA-B73.

https://arctichealth.org/en/permalink/ahliterature64593
Source
Eur J Immunogenet. 1995 Jun;22(3):231-40
Publication Type
Article
Date
Jun-1995
Author
H J Hoffmann
T J Kristensen
T G Jensen
B. Graugaard
L U Lamm
Author Affiliation
Department of Clinical Immunology, Skejby University Hospital, Aarhus, Denmark.
Source
Eur J Immunogenet. 1995 Jun;22(3):231-40
Date
Jun-1995
Language
English
Publication Type
Article
Keywords
Amino Acid Sequence
Animals
Base Sequence
Cell Line, Transformed
Cercopithecus aethiops
DNA, Complementary - genetics
Denmark
Female
Gene Frequency
Genes, MHC Class I
HLA-B Antigens - chemistry - genetics - immunology
Histocompatibility testing
Humans
Isoantibodies - immunology - isolation & purification
Kidney Transplantation
Male
Mass Screening
Models, Molecular
Molecular Sequence Data
Parity
Paternity
Pregnancy
Protein Conformation
Recombinant Fusion Proteins - biosynthesis
Transfection
Trophoblasts - immunology
Abstract
The cDNA sequence and serological data for HLA-B73 are reported. Anti-B73 sera are found relatively frequently, considering the rarity of the antigen. It was noted early that in some cases the antibodies in sera of multiparous women did not react with the eliciting cells (fathers) and thus all behaved as a naturally occurring antibody. We report on 18 B73 antisera found during the screening of 55,000 Danish sera. Only one of the 17 stimulators typed also had the B73 tissue type. Ten of the stimulators had antigens from the B7 CREG (B7, B22, B27, B42, B67, B73), whereas none of the responders had such tissue types. In seven cases the serum was not able to react with the stimulator's lymphocytes in a cytotoxicity assay and in four cases the stimulator lymphocytes could not deplete the anti-B73 activity from the serum in absorption experiments. The cDNA of B73 was expressed correctly in COS cells and was recognized on the cell surface by a monospecific serum. The alpha 1 alpha 2 domains of B73 are most similar to those of the HLA-B22 family. Interestingly, the alpha 3 and transmembrane domains of HLA-B73 are not standard human domains, but are most similar to the corresponding domains of some gorilla and chimpanzee HLA-B genes.
PubMed ID
8547229 View in PubMed
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Arctic adaptation in reindeer. The energy saving of a hemoglobin.

https://arctichealth.org/en/permalink/ahliterature230968
Source
FEBS Lett. 1989 Apr 10;247(1):135-8
Publication Type
Article
Date
Apr-10-1989
Author
B. Giardina
O. Brix
M. Nuutinen
S. el Sherbini
A. Bardgard
G. Lazzarino
S G Condò
Author Affiliation
Department of Experimental Medicine and Biochemical Sciences, II University of Rome, Italy.
Source
FEBS Lett. 1989 Apr 10;247(1):135-8
Date
Apr-10-1989
Language
English
Publication Type
Article
Keywords
2,3-Diphosphoglycerate
Adaptation, Physiological
Animals
Chlorides - blood
Cold Temperature
Diphosphoglyceric Acids - blood
Energy Metabolism
Hemoglobins - metabolism
Humans
Hydrogen-Ion Concentration
Oxygen - blood
Protein Conformation
Reindeer - physiology
Temperature
Thermodynamics
Abstract
Previous results [(1988) Arct. Med. Res. 47, 83-88] have shown that hemoglobin from reindeer is characterized by a low overall heat of oxygenation. This particular aspect has been investigated further in a series of precise oxygen equilibrium experiments. The results obtained show a peculiar dependence of the temperature effect on the fractional saturation of hemoglobin with oxygen, which could be regarded as a very interesting case of molecular adaptation to extreme environmental conditions.
PubMed ID
2707444 View in PubMed
Less detail

Assays of fibrin network properties altered by VKAs in atrial fibrillation - importance of using an appropriate coagulation trigger.

https://arctichealth.org/en/permalink/ahliterature271201
Source
Thromb Haemost. 2015 Apr;113(4):851-61
Publication Type
Article
Date
Apr-2015
Author
Michal Zabczyk
Margareta Blombäck
Jacek Majewski
Grzegorz Karkowski
Hakan N Wallen
Anetta Undas
Shu He
Source
Thromb Haemost. 2015 Apr;113(4):851-61
Date
Apr-2015
Language
English
Publication Type
Article
Keywords
Acenocoumarol - therapeutic use
Aged
Anticoagulants - therapeutic use
Atrial Fibrillation - blood - complications - diagnosis - drug therapy
Blood Coagulation - drug effects
Case-Control Studies
Fibrin - metabolism - ultrastructure
Fibrin Clot Lysis Time
Humans
International Normalized Ratio
Microscopy, Electron, Scanning
Poland
Porosity
Protein Conformation
Sweden
Thrombin - metabolism
Thrombosis - blood - etiology - prevention & control
Vitamin K - antagonists & inhibitors - blood
Warfarin - therapeutic use
Abstract
Atrial fibrillation (AF) is a prothrombotic condition, involving increased thrombin generation and fibrinogen concentrations. Vitamin K antagonists (VKAs) prevent arterial thromboembolism if optimal anticoagulation is achieved by individualised drug doses, assessed by determining the Prothrombin time-related International Normalized Ratio (Pt-INR). There is evidence that formation of tight-laced fibrin networks is pathogenic in prothrombotic diseases. This study was performed among AF patients, to test whether long-term treatment with VKAs affects the structure of fibrin networks, and whether the effect is altered by employing different coagulation triggers: exogenous thrombin (1 IU/ml), 10 pM tissue factor (TF) or a commercial Pt-INR reagent (containing 400-fold more TF). In the thrombin-based method, fibrin network porosity (scanning electron microscopy) and liquid permeability (flow measurements) correlated inversely to fibrinogen concentrations, while positive correlations to the degree of anticoagulation were shown with the Pt-INR reagent. In the method with 10 pM TF, the two above relationships were detected, though the influence of Pt-INR was more profound than that of fibrinogen concentrations. Moreover, greater shortening of clot lysis time (CLT) arose from more permeable clots. As a coagulation trigger, 10 pM TF vs exogenous thrombin or the Pt-INR reagent is more informative in reflecting the in vivo process from thrombin generation to fibrin formation. Since fibrin network permeability rose in parallel to elevations of INR and shortening of CLT in AF patients, antithrombotic effects on prevention of thrombotic complications may be achieved from impairment of thrombin generation, resulting in formation of permeable clots susceptible to fibrinolysis.
PubMed ID
25518887 View in PubMed
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[Association of GNB3 gene C825T polymorphism with coronary heart disease].

https://arctichealth.org/en/permalink/ahliterature160636
Source
Genetika. 2007 Aug;43(8):1129-33
Publication Type
Article
Date
Aug-2007
Author
A G Nikitin
D A Chudakova
E V Spitsina
L O Minushkina
D A Zateishchikov
V V Nosikov
V G Debabov
Source
Genetika. 2007 Aug;43(8):1129-33
Date
Aug-2007
Language
Russian
Publication Type
Article
Keywords
Aged
Case-Control Studies
Coronary Disease - genetics
European Continental Ancestry Group - genetics
Female
Gene Frequency
Genetic markers
Genetic Predisposition to Disease
Heterotrimeric GTP-Binding Proteins - chemistry - genetics
Humans
Male
Middle Aged
Polymorphism, Single Nucleotide
Protein Conformation
Russia
Abstract
The C825T polymorphism in the gene encoding the G protein beta 3 subunit (GNB3) causes enhanced G protein activation and the increased in vitro cell proliferation. We investigated the association of gene GNB3 C825T polymorphism with coronary artery disease (CAD) in the Russian population. A total of 313 patients with CAD diagnosed on the basis of clinical studies and coronary angyography were examined. The control group included 132 individuals that lacked clinical CAD symptoms and had matching profile of coronary artery disease risk factors. Blood pressure was measured using standard protocols. Increased levels of diastolic and systolic pressure was observed in both groups. The allele and genotype frequencies of this polimorphic marker were significantly higher in the CAD patients than in control. We found that the frequency of allele C and gen-. otype CC was significantly higher in the CAD patients (OR = 1.55; P = 0.0079; OR = 1.63; P = 0.0215, respectively), which suggests higher risk of this pathology in carriers of allele C and genotype CC. Thus, in the Russian population coronary artery disease is associated with GNB3 allele C and genotype CC.
PubMed ID
17958314 View in PubMed
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78 records – page 1 of 8.