Search results for "Teas"
showing 10 items of 619 documents
Cis autocatalytic cleavage of glycine-linked Zika virus NS2B-NS3 protease constructs.
2019
The flaviviral heterodimeric serine protease NS2B-NS3, consisting of the NS3 protease domain and the NS2B co-factor, is essential for ZIKA virus maturation and replication in cells. For in vitro studies a 'linked' construct, where a polyglycine linker connects NS2BCF and NS3pro , is often used. This construct undergoes autocatalytic cleavage. Here, we show that linked ZIKV NS2BCF -NS3pro is cleaved in cis in the NS2BCF exclusively at position R95 and not at the previously proposed alternate cleavage site at residue R29 in the NS3pro . Cleavage neither affects protease stability nor activity, despite some observed differences in spectroscopic behavior. This minimally modified construct may t…
The NS3/4A proteinase of the hepatitis C virus: unravelling structure and function of an unusual enzyme and a prime target for antiviral therapy
1999
The hepatitis C virus (HCV) is a major causative agent of transfusion-acquired and sporadic non-A, non-B hepatitis worldwide. Infections most often persist and lead, in approximately 50% of all patients, to chronic liver disease. As is characteristic for a member of the family Flaviviridae, HCV has a plus-strand RNA genome encoding a polyprotein, which is cleaved co- and post-translationally into at least 10 different products. These cleavages are mediated, among others, by a virally encoded chymotrypsin-like serine proteinase located in the N-terminal domain of non-structural protein 3 (NS3). Activity of this enzyme requires NS4A, a 54-residue polyprotein cleavage product, to form a stable…
Proteomic identification of protease cleavage sites characterizes prime and non-prime specificity of cysteine cathepsins B, L, and S.
2011
Cysteine cathepsins mediate proteome homeostasis and have pivotal functions in diseases such as cancer. To better understand substrate recognition by cathepsins B, L, and S, we applied proteomic identification of protease cleavage sites (PICS) for simultaneous profiling of prime and non-prime specificity. PICS profiling of cathepsin B endopeptidase specificity highlights strong selectivity for glycine in P3' due to an occluding loop blocking access to the primed subsites. In P1', cathepsin B has a partial preference for phenylalanine, which is not found for cathepsins L and S. Occurrence of P1' phenylalanine often coincides with aromatic residues in P2. For cathepsin L, PICS identifies 845 …
Structural requirements for V2 vasopressin receptor proteolytic cleavage.
1999
The ligand-induced proteolytic cleavage of the V2 vasopressin receptor transiently expressed in COS cells was investigated. After incubation of the cell membranes with a photoreactive ligand possessing full agonistic properties for V2 receptors, approximately 90% of the porcine and bovine V2 vasopressin receptors were cleaved in the upper part of transmembrane helix 2 at a heptapeptide sequence conserved in both vasopressin and oxytocin receptors. The oxytocin receptor was completely resistant to proteolysis after binding the same photoreactive ligand, which is only a partial agonist for this receptor. Chimeric V2/oxytocin receptors obtained by transfer of extracellular domains of the oxyto…
Toward very potent, non-covalent organophosphonate inhibitors of cathepsin C and related enzymes by 2-amino-1-hydroxy-alkanephosphonates dipeptides
2013
Cathepsins play an important role in several human disorders and therefore the design and synthesis of their inhibitors attracts considerable interest in current medicinal chemistry approaches. Due to the presence of a strong sulphydryl nucleophile in the active center of the cysteine type cathepsins, most strategies to date have yielded covalent inhibitors. Here we present a series of non-covalent β-amino-α-hydroxyalkanephosphonate dipeptidic inhibitors of cathepsin C, ranking amongst the best low-molecular weight inhibitors of this enzyme. Their binding modes determined by molecular modelling indicate that the hydroxymethyl fragment of the molecule, not the phosphonate moiety, acts as a t…
Comprehensive analysis of a Vibrio parahaemolyticus strain extracellular serine protease VpSP37
2015
Proteases play an important role in the field of tissue dissociation combined with regenerative medicine. During the years new sources of proteolytic enzymes have been studied including proteases from different marine organisms both eukaryotic and prokaryotic. Herein we have purified a secreted component of an isolate of Vibrio parahaemolyticus, with electrophoretic mobilities corresponding to 36 kDa, belonging to the serine proteases family. Sequencing of the N-terminus enabled the in silico identification of the whole primary structure consisting of 345 amino acid residues with a calculated molecular mass of 37.4 KDa. The purified enzyme, named VpSP37, contains a Serine protease domain be…
Structure, interdomain dynamics, and pH-dependent autoactivation of pro-rhodesain, the main lysosomal cysteine protease from African trypanosomes
2021
AbstractRhodesain is the lysosomal cathepsin L-like cysteine protease ofT. brucei rhodesiense, the causative agent of Human African Trypanosomiasis. The enzyme is essential for the proliferation and pathogenicity of the parasite as well as its ability to overcome the blood-brain barrier of the host. Lysosomal cathepsins are expressed as zymogens with an inactivating pro-domain that is cleaved under acidic conditions. A structure of the uncleaved maturation intermediate from a trypanosomal cathepsin L-like protease is currently not available. We thus established the heterologous expression ofT. brucei rhodesiensepro-rhodesain inE. coliand determined its crystal structure. The trypanosomal pr…
A Primary Evaluation of Potential Small-Molecule Inhibitors of the Astacin Metalloproteinase Ovastacin, a Novel Drug Target in Female Infertility Tre…
2020
Abstract Despite huge progress in hormonal therapy and improved in vitro fertilization methods, the success rates in infertility treatment are still limited. A recently discovered mechanism revealed the interplay between the plasma protein fetuin‐B and the cortical granule‐based proteinase ovastacin to be a novel key mechanism in the regulation of fertilization. Upon sperm–egg fusion, cleavage of a distinct zona pellucida component by ovastacin destroys the sperm receptor, enhances zona robustness, and eventually provides a definitive block against polyspermy. An untimely onset of this zona hardening prior to fertilization would consequently result in infertility. Physiologically, this proc…
Small molecule inhibitors of Apaf-1-related caspase- 3/-9 activation that control mitochondrial-dependent apoptosis
2006
10 pages, 5 figures.-- PMID: 16341125 [PubMed].-- Available online Dec 9, 2005.
The crystal structure of a 250-kDa heterotetrameric particle explains inhibition of sheddase meprin β by endogenous fetuin-B
2021
Meprin β (Mβ) is a multidomain type-I membrane metallopeptidase that sheds membrane-anchored substrates, releasing their soluble forms. Fetuin-B (FB) is its only known endogenous protein inhibitor. Herein, we analyzed the interaction between the ectodomain of Mβ (MβΔC) and FB, which stabilizes the enzyme and inhibits it with subnanomolar affinity. The MβΔC:FB crystal structure reveals a ∼250-kDa, ∼160-Å polyglycosylated heterotetrameric particle with a remarkable glycan structure. Two FB moieties insert like wedges through a “CPDCP trunk” and two hairpins into the respective peptidase catalytic domains, blocking the catalytic zinc ions through an “aspartate switch” mechanism. Uniquely, the …