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Biomedical subjects

X Ysern

Publications and source records attributed to X Ysern.

24 records · Page 2Linked to original sources
PubMed1989

Crystallization and preliminary X-ray diffraction studies of an anti-4-hydroxy-3-nitrophenylacetic acid monoclonal antibody Fab fragment complexed with immunizing and heteroclitic haptens.

The Fab fragment of the anti-4-hydroxy-3-nitrophenylacetic acid monoclonal antibody, 88C6/12 has been crystallized in the presence of the eliciting hapten, 4-hydroxy-3-nitrophenacetyl-epsilon-aminocaproic acid (NP-aminocap) and the heteroclitic iodinated analog, 4-hydroxy-3-iodo-5-nitrophenylacetyl-epsilon-aminocaproic acid (NIP-aminocap). Crystals obtained by precipitation with 32% (w/v) polyethylene glycol 3400 in the presence of 40 to 400 microM of either NP-aminocap or NIP-aminocap, belong to the orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 81.2 A, b = 86.9 A, c = 131.1 A. The cell volume suggests the presence of two molecules of the complex per asymmetric unit. Analysis of the Patterson function indicates that these two molecules are related by a local 2-fold axis parallel to the crystallographic b axis located at x = 0.218 and z = 0.25.

Antibodies, Monoclonal↗
PubMed1989

X-ray diffraction analyses of crystals of rat liver NAD(P)H:(quinone-acceptor) oxidoreductase containing cibacron blue.

NAD(P)H:(quinone-acceptor) oxidoreductase (EC 1.6.99.2) is a widely distributed dicoumarol-inhibitable FAD-containing protein that catalyzes the obligatory two-electron reduction of quinones. The enzyme plays an important role in protecting animal cells against quinone toxicity and may be involved in the vitamin K-dependent blood coagulation cascade. Cocrystallization of rat liver quinone reductase with Cibacron blue, a potent inhibitor with respect to NAD(P)H, was achieved by the method of vapor diffusion in the presence of ammonium sulfate and low concentrations of polyethylene glycol. X-ray diffraction analysis showed these blue crystalline platelets to be monoclinic and to belong to the space group P2(1) (a = 71.6 A, b = 107.1 A, c = 87.8 A and beta = 92.60 degrees) with two dimers in the asymmetric unit. The crystals diffract to a resolution of at least 2.8 A.

Ammonium Sulfate↗
PubMed1988

ATP synthases--structure of the F1-moiety and its relationship to function and mechanism.

A great deal of progress has been made in understanding both the structure and the mechanism of F1-ATPase. The primary structure is now fully known for at least five species. Sequence comparison between chloroplast, photobacteria, aerobic bacteria, and mitochondrial representatives allow us to infer more general functional relationships and evolutionary trends. Although the F1 moiety is the most studied segment of the H+-ATPase complex, there is not a full understanding of the mechanism and regulation of its hydrolytic activity. The beta subunit is now known to contain one and probably two nucleotide binding domains, one of which is believed to be a catalytic site. Recently, two similar models have been proposed to attempt to describe the "active" part of the beta subunits. These models are mainly an attempt to use the structure of adenylate kinase to represent a more general working model for nucleotide binding phosphotransferases. Labelling experiments seem to indicate that several critical residues outside the region described by the "adenylate kinase" part of this model are also actively involved in the ATPase activity. New models will have to be introduced to include these regions. Finally, it seems that a consensus has been reached with regard to a broad acceptance of the asymmetric structure of the F1-moiety. In addition, recent experimental evidence points toward the presence of nonequivalent subunits to describe the functional activity of the F1-ATPase. A summary diagram of the conformational and binding states of the enzyme including the nonequivalent beta subunit is presented. Additional research is essential to establish the role of the minor subunits--and of the asymmetry they introduce in F1--on the physiological function of the enzyme.

Amino Acid Sequence↗
PubMed1986

Preliminary X-ray diffraction analysis of HhaII endonuclease-DNA cocrystals.

HhaII restriction endonuclease purified from an overproducing recombinant E. coli clone has been cocrystallized with a heptanucleotide duplex, d-GGAGTCC:GGACTCC. The cocrystals are monoclonic and belong to the space group C2. The unit cell dimensions are a = 199.0 +/- 1.0 A, b = 100.0 +/- 0.5 A, c = 80.3 +/- 0.4 A, and beta = 101.0 +/- 1.0 degrees. There appear to be two dimers per asymmetric unit and the crystals diffract to 4-A resolution.

Base Sequence↗
PubMed1983

Comparative studies of pig platelet membrane proteins.

The proteins and glycoproteins of pig platelet membranes have been studied using gel electrophoretic techniques. A nomenclature is suggested from the apparent molecular weights estimated by one-dimensional electrophoresis. Isoelectric focusing showed that the majority of the proteins are in the 4.0-7.0 pH range. Subunits have been inferred from oligoproteins by two-dimensional, reduced-nonreduced, electrophoresis techniques. High resolution two dimensional electrophoresis combining isoelectric focusing and sodium dodecyl sulphate allows the observations of 60 polypeptide bands. An identification of some of those bands based on a correlation from reported human blood platelet membrane proteins is presented for comparison.

Animals↗