Search results for "Endopeptidase"
showing 10 items of 361 documents
Microbial and histopathological study of the vibriosis caused by Vibrio vulnificus serovar E in eels: The metalloprotease Vvp is not an essential les…
2008
Vibrio vulnificus biotype 2 serovar E (Bt2-serE) is a zoonotic pathogen that causes a haemorrhagic septicaemia in eels, called warm water vibriosis. The main objective of the present work was to study the onset of the eel vibriosis from the microbiological and histopathological viewpoint, as well as to ascertain the role of the protease Vvp as a lesional factor by comparing the histopathological lesions caused by the wild strain and its vvp deficient derivative. The wild-type strain was observed to attach to the gills, where it multiplied following saturation dynamics, subsequently invading the blood stream and reaching the internal organs. Here it reached population sizes that are notably …
Transporter (TAP)- and proteasome-independent presentation of a melanoma-associated tyrosinase epitope.
2000
The melanosomal protein tyrosinase is considered as a target of specific immunotherapy against melanoma. Two tyrosinase-derived peptides are presented in association with HLA-A2.1 [Wolfel et al., Eur. J. Immunol., 24, 759-764 (1994)]. Peptide 1-9 (MLLAVLYCL) is generated from the putative signal sequence. The internal peptide 369-377 is posttranslationally converted at residue 371, and its presentation is dependent on functional TAP transporters and proteasomes [Mosse et al., J. exp. Med.187, 37-48 (1998)]. Herein, we report on the processing and transport requirements for the signal sequence-derived peptide 1-9 that were studied in parallel to those for peptide 369-377. After infection of …
Sequence of the M28 dsRNA: Preprotoxin Is Processed to an α/β Heterodimeric Protein Toxin
1995
The killer and immunity phenotypes of K28 killer strains of Saccharomyces cerevisiae are determined by the 1.75-kb M28 dsRNA virus. In the plus strand, M28p, the K28 preprotoxin gene, comprises bases 13-1047 and is followed, after an additional 85 bases, by a 63-bp poly(A) sequence and a 553-base 3'-sequence. This 3'-sequence contains two potential stem-loop structures predicted to bind the L-A encoded cap-pol protein, initiating encapsidation; high-level expression results in curing of M1 dsRNA. Expression of M28p confers the complete K28 killer and immunity phenotype on a cell lacking M28 dsRNA. K28 toxin is a disulfide-bonded heterodimer of alpha (10.5 kDa) and beta (11 kDa) components w…
The nucleotide and deduced amino acid structures of sheep and pig fetuin. Common structural features of the mammalian fetuin family
1992
This study was initiated to gain further insight into the structural features of the mammalian fetuin family. The cDNA structures of sheep and pig fetuin were determined. The cDNA insert encoding sheep (pig) fetuin comprised 1550 (1470) nucleotides, including 54 (46) nucleotides encoding a signal peptide of 18 (15) residues and 1038 (1041) nucleotides encoding the 346 (347) amino acids of the mature plasma protein. The predicted amino-terminal sequence of the mature pig fetuin was confirmed by the amino-terminal sequence of the purified protein. However, two alternative sheep amino-terminal sequences were found in fetuin purified from the plasma of a single sheep fetus; the minor product wa…
Identification and characterization of onchoastacin, an astacin-like metalloproteinase from the filaria Onchocerca volvulus
2007
Abstract The tissue-invasive nematode Onchocerca volvulus causes skin and eye pathology in human onchocerciasis. While the adult females reside sessile in subcutaneous nodules, the microfilariae are abundantly released from the nodules, males and juvenile worms migrate through the host tissue. Matrix-degrading metallo- and serine proteinases have been detected in excretory-secretory worm products that may be essential for migration of the mobile stages. In this study, a 1713 bp long cDNA encoding for a putative proteinase of O. volvulus has been isolated. The predicted protein sequence includes a signal peptide indicating secretion to the extracellular space, a propeptide, an astacin-like p…
Pyrrolomycins as antimicrobial agents. Microwave-assisted organic synthesis and insights into their antimicrobial mechanism of action
2019
Abstract New compounds able to counteract staphylococcal biofilm formation are needed. In this study we investigate the mechanism of action of pyrrolomycins, whose potential as antimicrobial agents has been demonstrated. We performed a new efficient and easy method to use microwave organic synthesis suitable for obtaining pyrrolomycins in good yields and in suitable amount for their in vitro in-depth investigation. We evaluate the inhibitory activity towards Sortase A (SrtA), a transpeptidase responsible for covalent anchoring in Gram-positive peptidoglycan of many surface proteins involved in adhesion and in biofilm formation. All compounds show a good inhibitory activity toward SrtA, havi…
Discovery and structure-activity relationship studies of irreversible benzisothiazolinone-based inhibitors against Staphylococcus aureus sortase A tr…
2014
Gram-positive bacteria, in general, and staphylococci, in particular, are the widespread cause of nosocomial and community-acquired infections. The rapid evolvement of strains resistant to antibiotics currently in use is a serious challenge. Novel antimicrobial compounds have to be developed to fight these resistant bacteria, and sortase A, a bacterial cell wall enzyme, is a promising target for novel therapies. As a transpeptidase that covalently attaches various virulence factors to the cell surface, this enzyme plays a crucial role in the ability of bacteria to invade the host's tissues and to escape the immune response. In this study we have screened a small molecule library against rec…
Altered pore-forming properties of proteolytically nicked staphylococcal alpha-toxin
1993
Staphylococcal alpha-toxin is a single-chain polypeptide with a molecular weight of 34,000 that hexamerizes in lipid bilayers to form pores of 1-1.5 nm effective diameter in membranes. We demonstrate that limited proteolysis of purified alpha-toxin with proteinase K generates a hemolytically active product that yields one major protein band of 17-18 kDa in SDS-polyacrylamide gel electrophoresis. The 17-18-kDa protein band harbors two major fragments of similar size representing the N- and C-terminal halves, which remain associated with each other in non-denaturing buffers but dissociate in 6 M urea. Dissociation in urea leads to loss of hemolytic activity. In contrast, unnicked alpha-toxin …
Novel pathogenic mechanism of microbial metalloproteinases: liberation of membrane-anchored molecules in biologically active form exemplified by stud…
1996
Certain membrane-anchored proteins, including several cytokines and cytokine receptors, can be released into cell supernatants through the action of endogenous membrane-bound metalloproteinases. The shed molecules are then able to fulfill various biological functions; for example, soluble interleukin-6 receptor (sIL-6R) can bind to bystander cells, rendering these cells sensitive to the action of IL-6. Using IL-6R as a model substrate, we report that the metalloproteinase from Serratia marcescens mimics the action of the endogenous shedding proteinase. Treatment of human monocytes with the bacterial protease led to a rapid release of sIL-6R into the supernatant. This effect was inhibitable …
Asymmetric Disulfanylbenzamides as Irreversible and Selective Inhibitors of Staphylococcus aureus Sortase A
2020
Abstract Staphylococcus aureus is one of the most frequent causes of nosocomial and community‐acquired infections, with drug‐resistant strains being responsible for tens of thousands of deaths per year. S. aureus sortase A inhibitors are designed to interfere with virulence determinants. We have identified disulfanylbenzamides as a new class of potent inhibitors against sortase A that act by covalent modification of the active‐site cysteine. A broad series of derivatives were synthesized to derive structure‐activity relationships (SAR). In vitro and in silico methods allowed the experimentally observed binding affinities and selectivities to be rationalized. The most active compounds were f…