Molecular characterization of Trimeresurus stejnegeri venom L-amino acid oxidase with potential anti-HIV activity

A novel L-amino acid oxidase, named TSV-LAO, has been purified and cloned from the snake Trimeresurus stejnegeri. Fifty percentage cytotoxic concentrations (CC50) of TSV-LAO on C8166 cells were 24 and 390 nM in the absence or presence of catalase (400nM), respectively. However, at concentrations that showed little effect on cell viability, TSV-LAO displayed dose dependent inhibition on HIV-1 infection and replication. The antiviral selectivity indexes (CC50/EC50) were 16 and 6, respectively, corresponding to the measurements of syncytium formation and HIV-1 p24 antigen expression. Interestingly, the presence of catalase resulted in an increase of its antiviral selectivity to 52 and 38. Under the same conditions, no anti-HIV-1 activity was observed by exogenous addition of H2O2. The complete amino acid sequence of TSV-LAO, as deduced from its cDNA, exhibits a high degree of sequence identity with other snake venom LAOs. (C) 2003 Elsevier Inc. All rights reserved.

Molecular characterization of L-amino acid oxidase from king cobra venom

An L-amino acid oxidase from Ophiophagus hannah snake venom (Oh-LAAO) was purified by successive gel filtration, ion-exchange and heparin chromatography. Oh-LAAO did not induce platelet aggregation; however, it had potent inhibitory activity on platelet a

A new anti-HIV lupane acid from Gleditsia sinensis Lam.

A new lupane acid, 2 beta-carboxyl, 3 beta-hydroxyl-norlupA (1)-20 (29)-en-28-oic acid (1), together with five known lupane acid derivatives (2-6), were isolated from the stings of Gleditsia sinensis Lam.. Their structures were elucidated on the basis of

L-amino acid oxidase from Naja atra venom activates and binds to human platelets

An L-amino acid oxidase (LAAO), NA-LAAO, was purified from the venom of Naja atra. Its N-terminal sequence shows great similarity with LAAOs from other snake venoms. NA-LAAO dose-dependently induced aggregation of washed human platelets. However, it had n

Purification and characterization of a new L-amino acid oxidase from Daboia russellii siamensis venom

A new L-amino acid oxidase (designated as DRS-LAAO) was purified from Daboia russellii siamensis venom by ion-exchange, gel filtration and affinity chromatographies. DRS-LAAO is a homodimeric enzyme with a molecular weight of 120.0 kDa as measured by size

Purification, characterization and biological activity of an L-amino acid oxidase from Trimeresurus mucrosquamatus venom

An L-amino acid oxidase (TM-LAO) from the venom of Hunan Trimeresurus mucrosquamatus was purified to homogenicity by three steps including DEAE Sephadex A-50 ion-exchange chromatography, Sephadex G-75 gel filtration and Resourse Q ion-exchange chromatography. TM-LAO is composed of two identical subunits with a molecular weight of 55 kD by SDS-polyacrylamide gel electrophoresis. The molecular weight was different with that of LAO purified from the same species distributed in Taiwan that was 70 kD. The 24 N-terminal ammo acid sequence of TM-LAO is ADNKNPLEECFRETNYEEFLEIAR, which shares high similarity with other Viperid snake venom LAOs and has moderate similarity with Elapid snake venom LAOs. Further studies found that TM-LAO inhibited the growth of E. colt, S. aurues and B. dysenteriae. TM-LAO also showed cytotoxicity and platelet aggregation activity. All the biological activities were eliminated by catalase, a H2O2 scavenger. It shows that these biological effects are possibly due to the formation of H2O2 produced by TM-LAO.

A single amino acid defines cross-species reactivity of tree shrew (Tupaia belangeri) CD1d to human invariant natural killer T (iNKT) cells

P>The non-classical major histocompatibility complex (MHC) class I molecule CD1d presents lipid antigens to invariant natural killer T (iNKT) cells, which are an important part of the innate immune system. CD1d/iNKT systems are highly conserved in evoluti

Comparison of quantum chemistry calculation methods of nucleic acid base-quartets

Nine base-quartets were calculated by six semi-empirical methods and ab initio Hartree-Fork method using STO-3G basis set. The results showed that PM3 method can be use to calculate base quartets, the results of PM3 calculations are close to the ab initio