Presenilin 1 and presenilin 2 are polytopic membrane proteins, whose genes are mutated in some individuals with Alzheimer's disease. Presenilins have been shown to influence limited proteolysis of amyloid beta protein precursor (APP), Notch and ErbB4, and have been proposed to be gamma-secretases that perform the terminal cleavage of APP. In this model, two conserved and apparently intramembran...

Cathepsin D is an important lysosomal aspartic protease and is transported to the lysosomes in both mannose 6-phosphate dependent and independent manner. The present study reports lysosomal transport and proteolytic characterization of cathepsin D purified from gonads of starfish Asterias Rubens. Activity of the purified enzyme was confirmed by a zymogram assay on hemoglobin. Characterization o...

The crystal structure of a 1:1 complex between the German cockroach allergen Bla g 2 and the Fab' fragment of a monoclonal antibody 7C11 was solved at 2.8-angstroms resolution. Bla g 2 binds to the antibody through four loops that include residues 60-70, 83-86, 98-100, and 129-132. Cation-pi interactions exist between Lys-65, Arg-83, and Lys-132 in Bla g 2 and several tyrosines in 7C11. In the ...

Plasmepsin V, a membrane-bound aspartic protease present in Plasmodium falciparum, is involved in the export of malaria parasite effector proteins into host erythrocytes and therefore is a potential target for antimalarial drug development. The present study reports the bacterial recombinant expression and initial characterization of zymogenic and mature plasmepsin V. A 484-residue truncated fo...

NopE1 is a type III-secreted protein of the symbiont Bradyrhizobium japonicum which is expressed in nodules. In vitro it exhibits self-cleavage in a duplicated domain of unknown function (DUF1521) but only in the presence of calcium. Here we show that either domain is self-sufficient for cleavage. An exchange of the aspartic acid residue at the cleavage site with asparagine prevented cleavage; ...

Protease-producing bacteria are widespread in ocean sediments and play important roles in degrading sedimentary nitrogenous organic materials. However, the diversity of the bacteria and the proteases involved in such processes remain largely unknown especially for communities in enclosed sea bays. Here, we investigated the diversity of the extracellular protease-producing bacteria and their pro...

The N terminus of the replicase nonstructural protein 2 (nsp2) of porcine reproductive and respiratory syndrome virus (PRRSV) contains a putative cysteine protease domain (PL2). Previously, we demonstrated that deletion of either the PL2 core domain (amino acids [aa] 47 to 180) or the immediate downstream region (aa 181 to 323) is lethal to the virus. In this study, the PL2 domain was found to ...

The invariant chain (Ii) is associated with major histocompatibility complex class II molecules during early stages of their intracellular transport. In an acidic endosomal/lysosomal compartment, it is proteolytically cleaved and removed from class II heterodimers. Participation of aspartic and cysteine proteases has been observed in in vitro degradation of Ii, but the specific enzymes responsi...

A novel bifunctional inhibitor (ATBI) from an extremophilic Bacillus sp. exhibiting an activity against phytopathogenic fungi, including Alternaria, Aspergillus, Curvularia, Colletotricum, Fusarium, and Phomopsis species, and the saprophytic fungus Trichoderma sp. has been investigated. The 50% inhibitory concentrations of ATBI ranged from 0.30 to 5.9 microg/ml, whereas the MIC varied from 0.60...

Human immunodeficiency virus type 1 (HIV-1) encodes a 22 kDa homodimeric aspartic protease that cleaves the gag and pol viral polyproteins at nine specific sites and thus permits viral maturation (Kohl et al., 1988). HIV-1 protease is one of the most extensively studied enzymes, both experimentally and computationally. Hence, the invention of drugs that restrict proteolytic processing by the pr...