Protein and Peptide Letters - Volume 10, Issue 4, 2003

Calmodulin (CaM) is an EF-hand Ca(II)-binding protein involved in the regulation of many important biological processes. To date, there is a wealth of information available concerning studies to obtain site-specific calcium binding affinities of CaM, and further to estimate the cooperativity of calcium binding using mutational studies, peptide models, and proteolytic fragmentation. In this paper, we will discuss the energetics of Read More

The polyphemusins present in the hemocytes of the horsechoe crab and their structurally modified analogs have been shown to exhibit activity against HIV-1. Among the many variants, T22 ([Tyr5,12, Lys7]-polyphemusin II), and its shorter and more potent analog, T140 [Arg1-Arg-2-Nal-Cys-Tyr5- Arg-Lys-D-Lys-Pro-Tyr10-Arg-Cit-Cys-Arg14] (Polyphemusin II-derived peptide), affect the HIV-cell fusion process and inhibit the T-ce Read More

Cry4B toxin is a mosquito-larvicidal protein from the Bacillus thuringiensis subsp. israelensis. We have investigated the role of two conserved hydrophobic residues of Cry4B in structural stabilization. Substitutions of the leucine-175 and isoleucine-189 on helix α5 with valine and leucine did not affect the expression level, solubility and proteolytic processing. Steady state analysis of an unfolding experiment as monitored by ci Read More

An alternative method for expressing the recombinant proteins in Escherichia coli is proposed. Unlike the ordinary induction protocol where the cells in the early- to mid-log phase are induced for the protein production, this alternative protocol utilizes the cells in the stationary phase. By using a glutathione S-transferase fusion protein as an example, the protocol proposed in this report yielded a higher amount of the desired pr Read More

The Cys69 residue of an Anopheles dirus glutathione S-transferase isoform (adGSTD3-3), was characterized to elucidate its contribution in both catalysis and structural support. Nine mutants were generated at this position by replacing the residue with polar, non-polar and charged residues. The polar residues changed the Vm of the enzymes. With non-polar residues, the enzymes were unable to fold and were expressed in th Read More

α-Hemoglobin fragments α-(133-141), α-(134-141), α-(135-141), α-(137-141), α-(134-140), α- (133-138), α-(134-140) and α-(137-138) stimulate L929 tumor cell proliferation, α-(134-141) being the most active. α-(134-141) stimulates proliferation of M3 melanoma cells, murine embryonic fibroblasts, primary cultures of red bone marrow and spleen cells. In L929 cells the effect of α-(134-141) is cell density independent; in Read More

Transglutaminase (TGase) has been reported to be involved in the regulation of cell growth. We examined the effects of polyamines on TGase activity. The polymerization of casein was inhibited by putrescine (PUT) and spermidine (SPD). On the other hand, polymerization of N,N-dimethylcasein was increased by spermine (SPM) and SPD. These results suggested polyamines played two distinct roles as inhibitor and Read More

The plasmid DNA pERilox4 containing the gene of the recombinant protein, which included the leader sequence and the oxytocinoyl lysine tetramer, was constructed. The high level of gene expression in E. coli was achieved. The method for purification of the recombinant protein and its isolation in the soluble form was developed. The conditions for digestion of the hybrid protein by trypsin and carboxypeptidase B were m Read More

The terminal oxygenase component of the biphenyl dioxygenase (BphA1A2 complex) was over-expressed with a novel over expression system in recombinant Rhodococcus strain and purified. The purified enzyme has been crystallized by the hanging drop vapor diffusion method and subjected to X-ray diffraction analysis. The crystals belong to the tetragonal system in the space group P4 1 2 1 2 or P4 3 2 1 2 and diffract to bett Read More

The ubiquitous NAD+ synthetase catalyzes the key step in the biosynthesis of nicotinamide adenine dinucleotide. NH3-dependent NAD+ synthetase from Helicobacter pylori was purified to homogeneity and crystallized using PEG 1500 as a preciptant. The crystal diffracted up to a resolution of 2.3+ and was found to belong to space group C2 with unit cell dimensions of a = 93.8, b = 48.3, c = 64.2 Å and α = γ = 90, β = 110.0°.

Hemoglobin D (Hb D) from the Aldabra giant tortoise, Geochelone gigantea, was crystallized by the hanging drop vapor diffusion technique with a precipitant solution containing 10% polyethylene glycol 3350 and 50 mM HEPES-Na, pH 7.5. The Hb D crystals of G. gigantea, which diffract to at least a 2.0 Å resolution, belong to the monoclinic space group C2 with unit cell dimensions of a = 112.1 Å, b = 62.4 Å, c = 54.0 Å, and β Read More