A ribonuclease inhibitor resistant dimer of human pancreatic ribonuclease displays specific antitumor activity.

Human pancreatic ribonuclease (HPR) and bovine seminal ribonuclease (BS-RNase) are members of the RNase A superfamily. HPR is monomeric, whereas BS-RNase is dimeric. BS-RNase has strong antitumor and cytotoxic activities.

Functional role of glutamine 28 and arginine 39 in double stranded RNA cleavage by human pancreatic ribonuclease.

Human pancreatic ribonuclease (HPR), a member of RNase A superfamily, has a high activity on double stranded (ds) RNA. By virtue of this activity HPR appears to be involved in the host-defense against pathogenic viruses. To delineate the mechanism of dsRNA cleavage by HPR, we have investigated the role of glutamine 28 and arginine 39 of HPR in its activity on dsRNA.

Role of unique basic residues of human pancreatic ribonuclease in its catalysis and structural stability.

Human pancreatic ribonuclease (HPR) and bovine RNase A belong to the RNase A superfamily and possess similar key structural and catalytic residues. Compared to RNase A, HPR has six extra non-catalytic basic residues and high double-stranded RNA (dsRNA) cleavage activity. We mutated four of these basic residues, K6, R32, K62, and K74 to alanine and characterized the variants for function and stability.

Human eosinophil-derived neurotoxin: involvement of a putative non-catalytic phosphate-binding subsite in its catalysis.

Human eosinophil-derived neurotoxin (EDN) or RNase 2, found in the non-core matrix of eosinophils is a ribonuclease belonging to the Ribonuclease A superfamily. EDN manifests a number of bioactions including neurotoxic and antiviral activities, which are dependent on its ribonuclease activity. The core of the catalytic site of EDN contains various base and phosphate-binding subsites.

Involvement of loops L2 and L4 of ribonucleolytic toxin restrictocin in its functional activity.

Restrictocin, a member of the fungal ribotoxin family, specifically cleaves a single phosphodiester bond in the 28S rRNA and potently inhibits eukaryotic protein synthesis. The long loops in restrictocin molecule have been shown structurally to be involved in target RNA recognition. In this study we have investigated the role of some putative substrate-interacting residues in loops L2 and L4, spanning residues 36-48 and 99-117, respectively in restrictocin catalysis.