Search results for "Fluorescent"

Characterization of the interaction between Actinin-Associated LIM Protein (ALP) and the rod domain of α-actinin

2009

Abstract Background The PDZ-LIM proteins are a family of signalling adaptors that interact with the actin cross-linking protein, α-actinin, via their PDZ domains or via internal regions between the PDZ and LIM domains. Three of the PDZ-LIM proteins have a conserved 26-residue ZM motif in the internal region, but the structure of the internal region is unknown. Results In this study, using circular dichroism and nuclear magnetic resonance (NMR), we showed that the ALP internal region (residues 107–273) was largely unfolded in solution, but was able to interact with the α-actinin rod domain in vitro, and to co-localize with α-actinin on stress fibres in vivo. NMR analysis revealed that the ti…

Structural characterisation of the natural membrane-bound state of melittin: a fluorescence study of a dansylated analogue

1997

Abstract The binding of a dansylated analogue of melittin (DNC–melittin) to natural membranes is described. The cytolytic peptide from honey bee venom melittin was enzymatically labelled in its glutamine-25 with the fluorescent probe monodansylcadaverine using guinea pig liver transglutaminase. The labelled peptide was characterised functionally in cytolytic assays, and spectroscopically by circular dichroism and fluorescence. The behaviour of DNC–melittin was, in all respects, indistinguishable from that of the naturally occurring peptide. We used resonance energy transfer to measure the state of aggregation of melittin on the membrane plane in synthetic and natural lipid bilayers. When bo…

Organelle pH studies using targeted avidin and fluorescein–biotin

2000

Abstract Background: Mammalian organelles of the secretory pathway are of differing pH. The pH values form a decreasing gradient: the endoplasmic reticulum (ER) is nearly neutral, the Golgi is mildly acidic and the secretory granules are more acidic still (∼pH 5). The mechanisms that regulate pH in these organelles are still unknown. Results: Using a novel method, we tested whether differences in H + ‘leak' and/or counterion conductances contributed to the pH difference between two secretory pathway organelles. A pH-sensitive, membrane-permeable fluorescein–biotin was targeted to endoplasmic-reticulum- and Golgi-localized avidin-chimera proteins in HeLa cells. In live, intact cells, ER pH (…

Probes for studying cholesterol binding and cell biology.

2011

Cholesterol is a multifunctional lipid in eukaryotic cells. It regulates the physical state of the phospholipid bilayer, is crucially involved in the formation of membrane microdomains, affects the activity of many membrane proteins, and is the precursor for steroid hormones and bile acids. Thus, cholesterol plays a profound role in the physiology and pathophysiology of eukaryotic cells. The cholesterol molecule has achieved evolutionary perfection to fulfill its different functions in membrane organization. Here, we review basic approaches to explore the interaction of cholesterol with proteins, with a particular focus on the high diversity of fluorescent and photoreactive cholesterol prob…

Describing the gingival involvement in a sample of 182 Italian predominantly oral mucous membrane pemphigoid patients: A retrospective series

2016

Background The oral cavity has been frequently described as the only site of involvement or as the first manifestation of mucous membrane pemphigoid (MMP), being the gingival tissues often involved, but usually this has been effusively detailed in limited case series. This is a retrospective evaluation of the gingival involvement in 182 Italian patients with oral MMP. Material and Methods The diagnosis of MMP was established by both clinical morphology and direct immunofluorescence finding. Patient information (age, gender, risk factors and medical status) and parameters of manifestation (lesions’ distribution, site and type) were detailed. Results The mean age was 62 years for women (n=137…

Clostridium ģints baktēriju noteikšana dzeramajā ūdenī izmantojot Fluorescento in situ hibridizāciju

2015

Bakalaura darba mērķis bija ātri un precīzi identificēt dzeramajā ūdenī Clostridium ģints baktērijas izmantojot Fluorescento in situ hibridizāciju. Līdz ar to tika izmērīts un salīdzināts fluorescences intensitātes līmenis dažādām Clostridium sugām, kā arī citiem mikroorganismiem izmantojot Clostridium spp. specifiskas fluorescentās zondes. 92% no Clostridium acetobutylicum izmērītam šūnām, relatīvās gaismas vienības (RLU) pārsniedza 500 vienību robežu, 99% no Clostridium beijernickii un 96% no Clostridium tetahomorphum, salīdzinājumā ar Sphingomonas paucimobilis, kur tikai 2% pārsniedza 300 RLU. Veiktais variācijas analīzes tests (ANOVA) liecināja, ka starp Clostridium ģints baktērijām un …

Reorganization of Nuclear Domain 10 Induced by Papillomavirus Capsid Protein L2

2002

AbstractNuclear domains (ND) 10 are associated with proteins implicated in transcriptional regulation, growth suppression, and apoptosis. We now show that the minor capsid protein L2 of human papillomavirus (HPV) type 33 induces a reorganization of ND10-associated proteins. Whereas the promyelocytic leukemia protein, the major structural component of ND10, was unaffected by L2, Sp100 was released from ND10 upon L2 expression. The total cellular amount of Sp100, but not of Sp100 mRNA, decreased significantly, suggesting degradation of Sp100. Proteasome inhibitors induced the dispersal of Sp100 and inhibited the nuclear translocation of L2. In contrast to Sp100, Daxx was recruited to ND10 by …

In Vivo Imaging of Enteric Neuronal Networks in Humans Using Confocal Laser Endomicroscopy

2012

Interaction ofEscherichia colihemolysin with biological membranes

2001

Escherichia coli hemolysin (HlyA) is a membrane-permeabilizing protein belonging to the family of RTX-toxins. Lytic activity depends on binding of Ca2(+) to the C-terminus of the molecule. The N-terminus of HlyA harbors hydrophobic sequences that are believed to constitute the membrane-inserting domain. In this study, 13 HlyA cysteine-replacement mutants were constructed and labeled with the polarity-sensitive fluorescent probe 6-bromoacetyl-2-dimethylaminonaphthalene (badan). The fluorescence emission of the label was examined in soluble and membrane-bound toxin. Binding effected a major blue shift in the emission of six residues within the N-terminal hydrophobic domain, indicating inserti…

Molecular architecture of a toxin pore: a 15-residue sequence lines the transmembrane channel of staphylococcal alpha-toxin.

1996

Staphylococcus aureus alpha-toxin is a hydrophilic polypeptide of 293 amino acids that produces heptameric transmembrane pores. During assembly, the formation of a pre-pore precedes membrane permeabilization; the latter is linked to a conformational change in the oligomer. Here, 41 single-cysteine replacement toxin mutants were thiol-specifically labelled with the polarity-sensitive fluorescent probe acrylodan. After oligomerization on membranes, only the mutants with acrylodan attached to residues in the sequence 118-140 exhibited a marked blue shift in the fluorescence emission maximum, indicative of movement of the fluorophore to a hydrophobic environment. Within this region, two functio…