The effect of caesium chloride on the tertiary structure of the water-soluble pig gastric mucus

1972 ◽  
Vol 128 (4) ◽  
pp. 123P-124P
Author(s):  
D Snary ◽  
A Allen ◽  
R H Pain
1974 ◽  
Vol 141 (3) ◽  
pp. 641-646 ◽  
Author(s):  
David Snary ◽  
Adrian Allen ◽  
Roger H. Pain

1. Caesium chloride and guanidinium chloride were shown to cause conformational changes in the high-molecular-weight mucoprotein A of water-soluble gastric mucus with no change in molecular weight. 2. Increasing concentrations of CsCl decrease the viscosity of the mucoprotein bringing about a transition which is essentially complete in 0.1m-CsCl. The shear-dependence of viscosity of the mucoprotein is abolished by low concentrations of CsCl. The normally highly expanded molecule becomes contracted in CsCl to a molecule having the same symmetry but a smaller volume and decreased solvation, in keeping with an increased sedimentation coefficient (18.7S→33S). 3. This contracted form does not revert to the native conformation on removal of the CsCl. 4. A mechanism is discussed in terms of the effect of the Cs+and Cl−ions on water structure and the water–mucoprotein interaction. 5. Guanidinium chloride causes the CsCl-treated material to expand, in keeping with a decrease in s025,w (33S→26S). This is analogous to the known unfolding effect of guanidinium chloride on proteins and suggests that guanidinium chloride solubilizes groups involved in stabilizing the contracted structure. Removal of the guanidinium chloride results in a limited aggregation of four mucoprotein molecules. 6. These results show that caution must be exercised before interpreting the physical properties of mucoproteins which have been treated with CsCl and/or guanidinium chloride.


2004 ◽  
Vol 186 (21) ◽  
pp. 7420-7428 ◽  
Author(s):  
Beronda L. Montgomery ◽  
Elena Silva Casey ◽  
Arthur R. Grossman ◽  
David M. Kehoe

ABSTRACT All known phycobiliproteins have light-harvesting roles during photosynthesis and are found in water-soluble phycobilisomes, the light-harvesting complexes of cyanobacteria, cyanelles, and red algae. Phycobiliproteins are chromophore-bearing proteins that exist as heterodimers of α and β subunits, possess a number of highly conserved amino acid residues important for dimerization and chromophore binding, and are invariably 160 to 180 amino acids long. A new and unusual group of proteins that is most closely related to the allophycocyanin members of the phycobiliprotein superfamily has been identified. Each of these proteins, which have been named allophycocyanin-like (Apl) proteins, apparently contains a 28-amino-acid extension at its amino terminus relative to allophycocyanins. Apl family members possess the residues critical for chromophore interactions, but substitutions are present at positions implicated in maintaining the proper α-β subunit interactions and tertiary structure of phycobiliproteins, suggesting that Apl proteins are able to bind chromophores but fail to adopt typical allophycocyanin conformations. AplA isolated from the cyanobacterium Fremyella diplosiphon contained a covalently attached chromophore and, although present in the cell under a number of conditions, was not detected in phycobilisomes. Thus, Apl proteins are a new class of photoreceptors with a different cellular location and structure than any previously described members of the phycobiliprotein superfamily.


1960 ◽  
Vol 37 (4) ◽  
pp. 889-907 ◽  
Author(s):  
TORKEL WEIS-FOGH

1. A new type of hyaline, colourless cuticle, called rubber-like cuticle, is described and analysed qualitatively with respect to mechanical behaviour, structure and composition. Externally it is covered by ordinary thin epicuticle, but otherwise it represents the simplest type of cuticle known and consists only of thin continuous lamellae of chitin (0-2 µ) separated and glued together by an elastic protein, resilin, not hitherto described. There are only traces of water-soluble substances present and resilin sometimes occurs as pure, hyaline patches more than 100 µ thick and suitable for macroscopic experiments. 2. In all physical respects, resilin behaves like a swollen isotropic rubber but the rigid experimental proof is given elsewhere (Weis-Fogh, 1961). An outstanding feature is the complete lack of flow not paralleled by other natural or synthetic rubbers. 3. Resilin resembles elastin but it is devoid of colour and has a different and characteristic amino-acid composition (Bailey & Weis-Fogh, 1961). The nature of the cross-linkages is unknown at present but they are extremely stable, of a co-valent type and different from other known cross-linkages in proteins. This accounts for its insolubility and resistance to all agents which do not break the peptide backbone. 4. Resilin is a structure protein in which the primary chains show little or no tendency to form secondary structures; they are bound together in a uniform three-dimensional network (the tertiary structure) with no potential limits as to size.


1972 ◽  
Vol 127 (3) ◽  
pp. 68P-69P
Author(s):  
D Snary ◽  
A Allen ◽  
R H Pain

2010 ◽  
Vol 57 (3) ◽  
Author(s):  
Ehsan Amin ◽  
Ali Akbar Saboury ◽  
Hassan Mansouri-Torshizi ◽  
Samane Zolghadri ◽  
Abdol-Khalegh Bordbar

Two structurally related compounds, phenyl dithiocarbamate sodium salt (I) and p-phenylene-bis (dithiocarbamate) sodium salt (II) were prepared by reaction of the parent aniline and p-phenylenediamine with CS₂ in the presence of sodium hydroxide. These water soluble compounds were characterized by spectroscopic techniques, IR, ¹H NMR and elemental analysis. The inhibitory effects of both compounds on both activities of mushroom tyrosinase (MT) from Agricus bisporus were studied at two temperatures, 27°C and 37°C. L-3, 4-dihydroxyphenylalanine (L-DOPA), and l-tyrosine were used as natural substrates for the catecholase and cresolase enzyme reactions, respectively. Kinetic analysis confirmed noncompetitive inhibition mode of I and mixed type of II on both activities of MT; I and II inhibit MT with inhibition constants (K(I)) of 300 µM and 4 µM, respectively. Analysis of thermodynamic parameters indicated predominant involvement of hydrophobic interactions in binding of I and electrostatic ones in binding of II to MT. It seems that II is a more potent MT inhibitor due to its two charged head groups able to chelate copper ions in the enzyme active site. Intrinsic fluorescence studies as a function of concentrations of both compounds showed unexpectedly quenching of emission intensity without any shift of emission maximum. Extrinsic ANS-fluorescence indicated that only binding of I induces limited changes in the tertiary structure of MT, in agreement with the postulated hydrophobic nature of the binding mechanism.


1974 ◽  
Vol 27 (2) ◽  
pp. 117 ◽  
Author(s):  
GB Fincher ◽  
BA Stone

The water-soluble polymeric components of wheat endosperm have been extracted by two different procedures and their chemical composition studied in detail. Water extracts of wheat flour that had first been treated with hot 80% ethanol contained only 2% protein, but if the ethanol treatment was omitted up to 20% of the extracted polymeric fraction was low-molecular-weight non-dialysable protein material. Density-gradient ultracentrifugation in caesium chloride solutions indicated that most of this protein was free, whereas the 2% protein in the water extract of ethanol-treated flottr was firmly bound to a polysaccharide. This bound protein (a peptide) was characterized by high levels of hydroxyproline (16-20% of the amino acids present).


2017 ◽  
Vol 398 (11) ◽  
pp. 1229-1236 ◽  
Author(s):  
Vasily Golotin ◽  
Olga Portnyagina ◽  
Natalia Chopenko ◽  
Natalia Kim ◽  
Valery Rasskazov ◽  
...  

AbstractOmpF porin from the outer membrane ofYersinia pseudotuberculosiswas cloned into pET-40b(+) plasmid. UsingE. coliRosetta (DE3) strain, MX medium, IPTG concentration of 0.2 mmand post-induction cultivation at 14°C overnight allowed us to obtain a water-soluble form of the recombinant protein (rs-OmpF). Rs-OmpF was shown to have the ordered spatial structure at the levels of secondary and tertiary structure. Rs-OmpF was found to be effective as diagnostic antigen in ELISA for pseudotuberculosis diagnostics.


Author(s):  
J. G. Robertson ◽  
D. F. Parsons

The extraction of lipids from tissues during fixation and embedding for electron microscopy is widely recognized as a source of possible artifact, especially at the membrane level of cell organization. Lipid extraction is also a major disadvantage in electron microscope autoradiography of radioactive lipids, as in studies of the uptake of radioactive fatty acids by intestinal slices. Retention of lipids by fixation with osmium tetroxide is generally limited to glycolipids, phospholipids and highly unsaturated neutral lipids. Saturated neutral lipids and sterols tend to be easily extracted by organic dehydrating reagents prior to embedding. Retention of the more saturated lipids in embedded tissue might be achieved by developing new cross-linking reagents, by the use of highly water soluble embedding materials or by working at very low temperatures.


Author(s):  
J. D. McLean ◽  
S. J. Singer

The successful application of ferritin labeled antibodies (F-A) to ultrathin sections of biological material has been hampered by two main difficulties. Firstly the normally used procedures for the preparation of material for thin sectioning often result in a loss of antigenicity. Secondly the polymers employed for embedding may non-specifically absorb the F-A. Our earlier use of cross-linked polyampholytes as embedding media partially overcame these problems. However the water-soluble monomers used for this method still extract many lipids from the material.


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