Bacillus licheniformis variant DY proteinase: specificity in relation to the geometry of the substrate recognition site.

S1-S4 specificity of the Bacillus licheniformis variant DY proteinase (subtilisin DY) was determined by a series of peptide nitroanilides. The broad S1 specificity is due to the relative flexibility of the binding loop, which exhibits a preference for phenylalanine and accepts poorly the side chains of alanine, valine, lysine, and especially that of glutamic acid, due probably to a steric repulsion by Asn 155 and the narrow entrance of the "pocket." Alanine in position P2 of the substrate is more favorable for the catalysis than glycine.

Contribution of disulfide bonds and calcium to Molluscan hemocyanin stability.

Disulfide bonds and calcium ions contribute significantly to the stability of the hemocyanin from the mollusc Rapana thomasiana grosse (gastropod). An extremely powerful protective effect of Ca2+ at a concentration of 100 mM (100% protection) against the destructive effect of reductants like dithiothreitol was observed. This is important for the practical application of molluscan hemocyanins in experimental biochemistry, immunology and medicine.

Asp49 phospholipase A(2)-elaidoylamide complex: a new mode of inhibition.

The inhibition of phospholipase A(2)s (PLA(2)s) is of pharmacological and therapeutic interest because these enzymes are involved in several inflammatory diseases. Elaidoylamide is a powerful inhibitor of a neurotoxic PLA(2) from the Vipera ammodytes meridionalis venom. The X-ray structure of the enzyme-inhibitor complex reveals a new mode of Asp49 PLA(2) inhibition by a fatty acid hydrocarbon chain.

The X-ray structure of a snake venom Gln48 phospholipase A2 at 1.9A resolution reveals anion-binding sites.

Phospholipase A2 is an "interfacial" enzyme and its binding to negatively charged surfaces is an important step during catalysis. The Gln48 phospholipase A2 from the venom of Vipera ammodytes meridionalis plays the role of chaperone and directs a toxic His48 PLA2 onto its acceptor. In the venom the two phospholipases A2 exist as a postsynaptic neurotoxic complex, Vipoxin.

Interactions of the neurotoxin vipoxin in solution studied by dynamic light scattering.

The neurotoxin vipoxin is the lethal component of the venom of Vipera ammodytes meridionalis. It is a heterodimer of a basic toxic His-48 phospholipase A2 (PLA2) and an acidic nontoxic Gln-48 PLA2. The shape of the neurotoxin and its separated components in solution as well as their interactions with calcium, the brain phospholipid phosphatidylcholine, and two inhibitors, elaidoylamide and vitamin E, were investigated by dynamic light scattering.

Crystallization and preliminary X-ray diffraction studies of a toxic phospholipase A2 from the venom of Vipera ammodytes meridionalis complexed to a synthetic inhibitor.

A toxic phospholipase A(2) (PLA(2)) is isolated from the neurotoxic complex Vipoxin, the major lethal component of the venom of Vipera ammodytes meridionalis. The enzyme is complexed to the synthetic inhibitor elaidoylamide and crystallized. The crystals belong to the space group P2(1)2(1)2(1), with unit cell dimensions a=46.

Structure-function relationships in the neurotoxin Vipoxin from the venom of Vipera ammodytes meridionalis.

The neurotoxic complex Vipoxin is the lethal component of the venom of Vipera ammodytes meridionalis, the most toxic snake in Europe. It is a complex between a toxic phospholipase A2 (PLA2) and a non-toxic and catalytically inactive protein, stabilizing the enzyme and reducing the activity and toxicity. Structure-function relationships in this complex were studied by spectroscopic methods.

The major extracellular protease of the nosocomial pathogen Stenotrophomonas maltophilia: characterization of the protein and molecular cloning of the gene.

Stenotrophomonas maltophilia is increasingly emerging as a multiresistant pathogen in the hospital environment. In immunosuppressed patients, these bacteria may cause severe infections associated with tissue lesions such as pulmonary hemorrhage. This suggests proteolysis as a possible pathogenic mechanism in these infections.