Protein and Peptide Letters - Volume 13, Issue 6, 2006

During the last years the cases and death due to hemostatic violations exceed that of tumors. Enormous efforts have devoted to the prevention and treatment of some diseases such as arterial thrombosis. Antistasin, a 15 kDa anticoagulant protein isolated from salivary glands of the Mexican leech Haementeria officinalis, has been shown to be a potent inhibitor of Factor Xa in the blood coagulation cascade. Some short analog Read More

The 1, 4, and 8 tyrosine (Tyr) residues on the PSII extrinsic 23 kDa protein were modified with 5, 10 or 40 mM N-acetylimidazole (NAI) respectively. The amount of rebound NAI-modified extrinsic 23 kDa protein was 98%, 80%, and 5% of that in the unmodified protein, respectively. These results indicate that the Tyr residues are absolutely essential to reconstitution ability. Further, the fluorescence and circular dichroism spectra a Read More

The effect of methanol and trifluoroethanol (TFE) on the structure and folding of molten globule state of procerain, a cysteine protease from Calotropis procera, was studied by circular dichroism spectroscopy. The magnitude of ellipticity at 215 nm, as a measure of β-sheet content, is dependent on the concentration of the TFE. Interestingly, a switch over from the β-sheet structure of the molten globule state to α-helix Read More

Since the solvent accessible surface area of proteins has been utilized as an important factor in the prediction of their thermodynamic properties, a simple and analytical method for its determination would contribute to protein structure prediction and analysis methods. We report the development of a simple and analytical method for the estimation of the accessible surface area of protein, consisting of linear function Read More

Added KCl increases the apparent Michaelis constant (Km ) of pyruvate for porcine muscle-type lactate dehydrogenase (100 mM KCl, 83%; 200 mM KCl, 188%). The effects of 100 mM KCl were fully reversed by 375 mM trimethylamine N-oxide (TMAO). TMAO (375-750 mM) partially reversed the effects of 200 mM KCl. TMAO as the sole solute, at concentrations up to 750 mM, had no effect on Km. This is atypical because compens Read More

Fibrolase is a non-hemorrhagic zinc metalloproteinase found in southern copperhead snake venom (Agkistrodon contortrix contortrix). It is capable of degrading fibrin clots that result from purified fibrinogen or blood plasma. The DNA of fibrolase was amplified by recursive PCR, and cloned into the pET25b(+) expression vector. The effect of coexpression of signalless versions of catalysts or molecular chaperones FkpA, Skp and Read More

Chemical probing of histidine residues using specific modifiers, iodoacetic acid (IAA) and diethylpyrocarbonate (DEP) resulted in the inactivation of phytase (phy A). The kinetic theory of the substrate reaction during the modification of enzyme activity was applied to a study of the kinetics of the course of inactivation of phytase by IAA and DEP. The results suggested that histidine residues are involved in the active site of the enzy Read More

Hepatopancreas of king crab Paralithodes camtschatica produces a metalloprotease, which belongs to the astacin family, as cDNA cloning and sequencing showed. The metalloprotease has been purified chromatographically to apparent homogeneity. The purification factor was 16 and activity recovery was 20%. pH and temperature optimum have been determined. In its properties (molecular weight, pI, metal content) Read More

Disulphide bridges involving juxtaposed half-cystines are observed in a number of protein three-dimensional structures analyzed from the Protein Data Bank. These disulphide bridges comprise a 'ring of 8-atoms' corresponding to Cα1-C'-N-Cα2-Cβ2-Sγ2-Sγ1-Cβ1-Cα1 in the two half-cystines. The presence of such disulphide bridges introduces a 'bend' or 'kink' in the protein polypeptide chain.

The equilibrium unfolding of ElysL, a homodimeric legume lectin, was studied using different denaturing agents such as guanidinium chloride (GdnHCl), temperature and pH. Simultaneously, changes in the secondary as well as tertiary structure of lectin were followed by CD spectroscopy examination in both far and near-UV region, respectively. The hydrophobic cluster binding dye, 1-anilino-8-naphthalene sulfonate (ANS), Read More

Hypervariability of the complementary determining regions in characteristic structure of Immnoglobulins and the distinct, cell-specific expressions of the genes coding for this important class of proteins pose intriguing problems in experimental and computational/informatics research requiring a special approach different from those for the other proteins. We present here an Average Linkage Hierarchical Clustering of the Homo Read More

Here, it is shown that amphiphilicity profiling based on the mean hydrophobic moment provides a simple visual guide for the identification of oblique orientated a-helices. The methodology has an efficiency of circa 70% and predicts that approximately 40% of transmembrane a-helices may possess these structures.

In this study, we used the 183 translation probabilities between RNA codons and mutated amino acids to construct the theoretical distributions of mutated amino acids in hemagglutinins of influenza A virus. We then compared the actual distributions of mutated amino acids from 953 hemagglutinins with their theoretical ones. The results demonstrated that mutated amino acids generally follow the direction of the theo Read More

Enzymes from extremely halophilic archaea require high concentration of salts for their proper folding and consequently are expressed as an unfolded and inactive form in Escherichia coli. Moderate halophile, which accumulates protein stabilizers, i.e., compatible solutes, is an attractive host cell for the recombinant production of heterologous proteins, since such protein stabilizers may help folding of expressed proteins. Read More

The molecular diversity of bovine τ obtained by three different preparation protocols was characterized by immunoblot analyses after two-dimensional gel electrophoresis. These analyses revealed that t was heterogeneously modified, that is, up to 20 spots separated along the pH gradient, mostly independent of the preparation protocol.

The C-terminal 232-419 amino acids fragment of endonuclease Sau3AI has been successfully expressed in Escherichia coli with 6 His at its N-terminal. After purification and crystallization, one completed 2.8 Å data set was collected using a Rigaku R-AXIS IV ++ diffractometer. The plate-like crystals belong to orthorhombic space group P212121 with the cell dimension of a = 34.75, b = 76.82, c = 123.59Å and contain one Read More

Mastoparans are tetradecapeptides found to be the major component of wasp venoms. These peptides possess a variety of biological activities. Three related mastoparans, mastoparan from Polistes jadwagae (MP-PJ), mastoparanX (MP-X) and its carboxyl-free C-terminal form (MP-X-COO-), were crystallized. X-ray diffraction data for them were collected at resolutions of 1.2 Å, 2.0 Å and 3.3 Å respectively.

Apoptosis plays an important role in maintaining the normal function of various tissues and organs in different species. Caspase-3 is a terminal caspases which plays an important role in the execution of apoptosis in all vertebrates. It was cloned from zebra fish embryos and its properties were identified through Western blotting and biological activity. In the cells over-expressing caspase-3, Western blotting with an anti-His-t Read More

The human chloride intracellular channel protein CLIC4 has been crystallized by the hanging-drop vapourdiffusion technique using trisodium citrate as the precipitant. The best crystals were obtained by the microseeding method. The crystals diffracted to 2.2 Å resolution and were found to belong to space group P121, with unit-cell parameters a = 73.19, b =86.05, c = 73.38 Å, β = 112.99° and three molecule per asymmetric unit.