scholarly journals Fluorescence quenching of human orosomucoid. Accessibility to drugs and small quenching agents

1985 ◽  
Vol 232 (3) ◽  
pp. 863-867 ◽  
Author(s):  
M L Friedman ◽  
K T Schlueter ◽  
T L Kirley ◽  
H B Halsall
Keyword(s):  
Sialic Acid ◽  
Fluorescence Quenching ◽  
Negative Charge ◽  
Binding Domain ◽  
Tryptophan Residue ◽  
Protein Core ◽  
Residue Removal ◽  
The Third ◽  
Acrylamide Quenching ◽  
Tryptophan Residues

The fluorescence behaviour of human orosomucoid was investigated. The intrinsic fluorescence was more accessible to acrylamide than to the slightly larger succinimide, indicating limited accessibility to part of the tryptophan population. Although I- showed almost no quenching, that of Cs+ was enhanced, and suggested a region of negative charge proximal to an emitting tryptophan residue. Removal of more than 90% of sialic acid from the glycan chains led to no change in the Cs+, I-, succinimide or acrylamide quenching, indicating that the negatively charged region originates with the protein core. Quenching as a function of pH and temperature supported this view. The binding of chlorpromazine monitored by fluorescence quenching, in the presence and in the absence of the small quenching probes (above), led to a model of its binding domain on orosomucoid that includes two tryptophan residues relatively shielded from the bulk solvent, with the third tryptophan residue being on the periphery of the domain, or affected allotopically and near the negatively charged field.

scholarly journals Interactions between apo-(d-β-hydroxybutyrate dehydrogenase) and phospholipids studied by intrinsic and extrinsic fluorescence

1986 ◽  
Vol 237 (2) ◽  
pp. 359-364 ◽  
Author(s):  
M S el Kebbaj ◽  
N Latruffe ◽  
M Monsigny ◽  
A Obrenovitch
Keyword(s):  
Conformational Changes ◽  
Negative Charge ◽  
Positive Charge ◽  
Tryptophan Residue ◽  
Fluorescence Energy Transfer ◽  
Hydrophobic Region ◽  
Phospholipid Liposomes ◽  
Tryptophan Residues ◽  
Beta Hydroxybutyrate ◽  
Fluorescence Energy

Interactions of D-beta-hydroxybutyrate dehydrogenase with phospholipids were investigated by both intrinsic- and extrinsic-fluorescence approaches. The intrinsic fluorescence, mainly caused by tryptophan residues, increased upon re-activation in the presence of phospholipids bearing a positive charge, i.e. phosphatidylcholine, but decreased in the presence of non-re-activating phospholipids with a negative charge. This indicates either that the environment of tryptophan residues is affected by charges rather than by hydrophobic chains of phospholipids, or that the enzyme undergoes different conformational changes depending on the nature of the phospholipids. On the other hand, the graph of the temperature-dependence of the fluorescence intensities of the enzyme embedded in dimyristoylphosphatidylcholine liposomes exhibits a break around 21 degrees C. This indicates either that at least one tryptophan residue is closely in contact with the hydrophobic chains of phospholipids or that there is a change in the environment of tryptophan residues owing to the physical state of the phospholipids. The addition of D-beta-hydroxybutyrate apo-dehydrogenase to phospholipid liposomes containing diphenylhexatriene (a fluorescent probe) increased the diphenylhexatriene fluorescence polarization. Moreover, there was a partial fluorescence energy transfer from tryptophan to diphenylhexatriene. These results strongly favour the possibility that there is a portion of the enzyme polypeptide chain inserted into the phospholipid hydrophobic region. All these results demonstrate that D-beta-hydroxybutyrate apo-dehydrogenase interacts with both polar and hydrophobic parts of phospholipids and leads to small, but essential, conformational changes of the enzyme.

scholarly journals Gliding Motility of Mycoplasma mobile on Uniform Oligosaccharides

2015 ◽  
Vol 197 (18) ◽  
pp. 2952-2957 ◽  
Author(s):  
Taishi Kasai ◽  
Tasuku Hamaguchi ◽  
Makoto Miyata
Keyword(s):  
Sialic Acid ◽  
Negative Charge ◽  
Gliding Motility ◽  
Solid Surfaces ◽  
Plastic Plate ◽  
Inhibitory Effects ◽  
Content Type ◽  
Critical Information ◽  
The Third

ABSTRACTThe binding and gliding ofMycoplasma mobileon a plastic plate covered by 53 uniform oligosaccharides were analyzed. Mycoplasmas bound to and glided on only 21 of the fixed sialylated oligosaccharides (SOs), showing that sialic acid is essential as the binding target. The affinities were mostly consistent with our previous results on the inhibitory effects of free SOs and suggested thatM. mobilerecognizes SOs from the nonreducing end with four continuous sites as follows. (i and ii) A sialic acid at the nonreducing end is tightly recognized by tandemly connected two sites. (iii) The third site is recognized by a loose groove that may be affected by branches. (iv) The fourth site is recognized by a large groove that may be enhanced by branches, especially those with a negative charge. The cells glided on uniform SOs in manners apparently similar to those of the gliding on mixed SOs. The gliding speed was related inversely to the mycoplasma's affinity for SO, suggesting that the detaching step may be one of the speed determinants. The cells glided faster and with smaller fluctuations on the uniform SOs than on the mixtures, suggesting that the drag caused by the variation in SOs influences gliding behaviors.IMPORTANCEMycoplasma is a group of bacteria generally parasitic to animals and plants. SomeMycoplasmaspecies form a protrusion at a pole, bind to solid surfaces, and glide in the direction of the protrusion. These procedures are essential for parasitism. Usually, mycoplasmas glide on mixed sialylated oligosaccharides (SOs) derived from glycoprotein and glycolipid. Since gliding motility on uniform oligosaccharides has never been observed, this study gives critical information about recognition and interaction between receptors and SOs.

Kinetics of the Antibody Recognition Site in the Third IgG-Binding Domain of Protein G

2016 ◽  
Vol 128 (33) ◽  
pp. 9719-9722 ◽  
Author(s):  
Supriya Pratihar ◽  
T. Michael Sabo ◽  
David Ban ◽  
R. Bryn Fenwick ◽  
Stefan Becker ◽  
...  
Keyword(s):  
Binding Domain ◽  
Recognition Site ◽  
Protein G ◽  
Antibody Recognition ◽  
The Third ◽  
Igg Binding ◽  
Kinetics Of

The Third IgG-Binding Domain from Streptococcal Protein G

1994 ◽  
Vol 243 (5) ◽  
pp. 906-918 ◽  
Author(s):  
Jeremy P. Derrick ◽  
Dale B. Wigley
Keyword(s):  
Binding Domain ◽  
Protein G ◽  
The Third ◽  
Igg Binding ◽  
Streptococcal Protein G

Fluorescent Properties of Firefly Luciferases and Their Complexes with Luciferin

2000 ◽  
Vol 20 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Ekaterina I. Dementieva ◽  
Elena A. Fedorchuk ◽  
Lubov Yu. Brovko ◽  
Alexander P. Savitskii ◽  
Natalya N. Ugarova
Keyword(s):  
Energy Transfer ◽  
Tryptophan Fluorescence ◽  
Tryptophan Residue ◽  
Amino Acid Residues ◽  
Photinus Pyralis ◽  
Fluorescent Properties ◽  
Effective Energy Transfer ◽  
Tryptophan Residues ◽  
Luciola Mingrelica

Fluorescence of luciferases from Luciola mingrelica (single tryptophanresidue, Trp-419) and Photinus pyralis (two tryptophan residues, Trp-417,Trp-426) was studied. Analysis of quenching of tryptophan fluorescenceshowed that the tryptophan residue conserved in all luciferases is notaccessible for charged quenchers, which is explained by the presence ofpositively and negatively charged amino acid residues in the close vicinityto it. An effective energy transfer from tryptophan to luciferin wasobserved during quenching of tryptophan fluorescence of both luciferaseswith luciferin. From the data on the energy transfer, the distance betweenthe luciferin molecule and Trp-417 (419) in the luciferin–luciferasecomplex was calculated: 11–15 Å for P. pyralis and 12–17Å for L. mingrelica luciferases. The role of the conserved Trp residuein the catalysis is discussed.

scholarly journals Probing the role of tryptophan residues in a cellulose-binding domain by chemical modification

1996 ◽  
Vol 5 (11) ◽  
pp. 2311-2318 ◽  
Author(s):  
Mark R. Bray ◽  
Neil R. Gilkes ◽  
Douglas G. Kilburn ◽  
R. Antony J. Warren ◽  
Lawrence P. Mcintosh ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Binding Domain ◽  
Cellulose Binding Domain ◽  
Tryptophan Residues ◽  
Cellulose Binding

scholarly journals Membrane insertion of the N-terminal α-helix of equinatoxin II, a sea anemone cytolytic toxin

2004 ◽  
Vol 384 (2) ◽  
pp. 421-428 ◽  
Author(s):  
Ion GUTIÉRREZ-AGUIRRE ◽  
Ariana BARLIČ ◽  
Zdravko PODLESEK ◽  
Peter MAČEK ◽  
Gregor ANDERLUH ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Lipid Membrane ◽  
Model Systems ◽  
Tryptophan Residue ◽  
Sea Anemones ◽  
Fluorescence Measurements ◽  
Tryptophan Residues ◽  
Equinatoxin Ii ◽  
Α Helix ◽  
Pore Forming Proteins

Equinatoxin II (Eqt-II) is a member of the actinoporins, a unique family of cytotoxins comprising 20 kDa pore-forming proteins isolated from sea anemones. Actinoporins bind preferentially to lipid membranes containing sphingomyelin, and create cation-selective pores by oligomerization of three to four monomers. Previous studies have shown that regions of Eqt-II crucial for its cytolytic mechanism are an exposed aromatic cluster and the N-terminal region containing an amphipathic α-helix. In the present study, we have investigated the transfer of the N-terminal α-helix into the lipid membrane by the use of three mutants containing an additional tryptophan residue in different positions within the amphipathic α-helix (Ile18→Trp, Val22→Trp and Ala25→Trp). The interaction of the mutants with different model systems, such as lipid monolayers, erythrocytes and ghost membranes, was extensively characterized. Intrinsic fluorescence measurements and the use of vesicles containing brominated phospholipids indicated a deep localization of the N-terminal amphipathic helix in the lipid bilayer, except for the case of Val22→Trp. This mutant is stabilized in a state immediately prior to final pore formation. The introduction of additional tryptophan residues in the sequence of Eqt-II has proved to be a suitable approach to monitor the new environments that surround defined regions of the molecule upon membrane interaction.

Sign in / Sign up

Export Citation Format

Share Document