Crystallization and preliminary X-ray analysis of S-III-SPIII, a phospholipase A2 isolated from the venom of Bothrops jararacussu.

Large single crystals have been obtained of S-III-SPIII, a phospholipase A(2) from the venom of Bothrops jararacussu. The crystals belong to the orthorhombic system space group C222, and diffract X-rays to a resolution of 1.9 Angstrom. Preliminary analysis reveals the presence of one molecule in the crystallographic asymmetric unit. The crystal structure is currently being determined using molecular replacement techniques.

Crystallization and preliminary X-ray diffraction studies of BnSP-6, a myotoxic phospholipase A2 from Bothrops neuwiedi venom

BnSP-6 (myotoxin I) is a phospholipase A2 homologue isolated from Bothrops neuwiedi pauloensis venom. Crystals of BnSP-6 were obtained which diffracted X-rays to 2.5 Angstrom resolution using a synchrotron radiation source at room temperature and belong to space group P3(1)21. The unit cell dimensions are a=b=57.7, c=131.1 Angstrom. The structure was solved by molecular replacement using the coordinates of bothropstoxin I from B. jararacussu venom. There are two molecules in the asymmetric unit.

Crystallization and preliminary X-ray diffraction analysis of three myotoxic phospholipases A2 from Bothrops brazili venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação de Hb A2 e Hb F em doadores de sangue de região malarígena da Amazônia Oriental brasileira por HPLC

In malaria endemic regions of Africa, resistance to infection by Plasmodium has been observed in under 6-month-old children, when there are higher fetal hemoglobin (Hb F) levels. Research performed in the São José do Rio Preto region, central-east Brazil, reported increased levels of Hb F in blood donors. The purpose of this work was to evaluate the A2 hemoglobin (Hb A2) and Hb F concentrations in blood donors deriving from the Brazilian malaria endemic region. Forty-five blood donor samples from Macapá, from patients with varying genders, ages and ethnic origins, were collected by venous puncture after informed consent was obtained. The samples were analyzed by High Performance Liquid Chromatography (HPLC) - System Variant (Bio-Rad). The HPLC demonstrated sensitivity and rapidity in the identification and measurement of the hemoglobins and gave precise results. Moreover, it provided measurement of hemoglobin variants, even when they were present in small amounts, providing a diagnosis of hemoglobinopathies. Hb F levels above the normal were observed in 33.3% of the analyzed samples. The presence of increased Hb F can suggest resistance to infection by Plasmodium falciparum, as there have been reports that infected red blood cells interfere in the development of the parasite.

Crystallographic and spectroscopic characterization of a molecular hinge: Conformational changes in bothropstoxin I, a dimeric Lys49 phospholipase A2 homologue

Bothropstoxin I(BthTX-I) from the venom of Bothrops jararacussu is a myotoxic phospholipase A2 (PLA2) homologue which, although catalytically inactive due to an Asp49-->Lys substitution, disrupts the integrity of lipid membranes by a Ca2+-independent mechanism, the crystal structures of two dimeric farms of BthLTX-I which diffract X-rays eo resolutions of 3.1 and 2.1 Angstrom have been determined, the monomers in both structures are related by an almost perfect twofold axis of rotation and the dimer interfaces are defined by contacts between the N-terminal alpha-helical regions and the tips of the beta-wings of partner monomers. Significant differences in the relative orientation of the monomers in the two crystal forms results in open and closed dimer conformations, Spectroscopic Investigations of BthTX-I in solution have correlated these conformational differences with changes in the intrinsic fluorescence emission of the single tryptophan residues located at the dimer interface, the possible relevance of this structural transition in the Ca2+-independent membrane damaging activity is discussed. (C) 1998 Wiley-Liss, Inc.

Crystal structure of myotoxin-II: A myotoxic phospholipase A2 - Homologue from Bothrops moojeni venom.

The crystal structure of Myotoxin-II (MjTX-II), a Lys49 PLA(2)-homologue from Bothrops moojeni venom has been determined and refined at 2.0 Angstrom to a crystallographic residual of 19.7% (R-free = 28.1%). MjTX-II is a dimer in the crystal, with the monomers in the asymmetric unit related by a two-fold symmetry axis running through the dimer interface. The dimers of MjTX-II and the Lys49 PLA(2) from B. asper venom are similar, however the relative orientations of the monomers suggests a flexible dimer interface, which serves as a hinge between the two molecules.

Modulation of the Pharmacological Activities of Secretory Phospholipase A2 from Crotalus durissus cascavella Induced by Naringin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A2 Noradrenergic Lesions Prevent Renal Sympathoinhibition Induced by Hypernatremia in Rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desnaturação de oxihemoglobinas humanas A, A2 e S pelo metodo de tampão isopropanol

Human oxyhaemoglobin A and A2 from normal individuals and oxyhaemoglobin S from patients with sickle cell anaemia and sickle cell trait were studied using Isopropanol/buffer method at 37°C and 40°C. Hb S was less stable than Hb A, whereas Hb A2 was considerably more stable than either. Denaturation of Hb S was dependent on temperature and its concentration. Between the patients with sickle cell trait it was not possible to verify the influence of the concentration probably due to the small range used (from 38% to 44%).