Protein and Peptide Letters - Volume 15, Issue 7, 2008

Protein hydration plays a crucial role in almost all aspects of biomolecular processes. In this research, we studied the hydration/dehydration-induced infrared amide I band-shift by using poly-L-lysine and bovine pancreas ribonuclease A as model polypeptides. It was found that a 1-4 cm-1 shift could be clearly distinguished for all regular secondary structures during protein thermal unfolding. This shift was proven to be due Read More

This study investigated the effects of Photorhabdus temperata infection on the activities of digestive enzymes of the sugarcane stalk borer Diatraea saccharalis. Non-infected D. saccharalis larvae present a major α-amylase, several proteinases, three sucrose hydrolases and two α-glucosidases in their midgut. Analysis of these hydrolases by electrophoresis and “in gel” assays showed that the activities of all enzymes decreased foll Read More

Glycation, a non-enzymatic reaction between glucose and protein is the primary cause of diabetic complications. Albumin, the most abundant plasma protein undergoes glycation both in vivo and in vitro. The influence of albumin on glycation of less abundant proteins has not been addressed. For the first time, we show that albumin competitively inhibits the glycation of less abundant proteins. This study suggests th Read More

The observation in 1979 that opioid receptors interact, led to the design of bivalent ligands in an attempt to improve selectivity and affinity towards the different subtypes (i.e. μ, δ and κ). Dimers of monovalent “parent” opioid structures have been evaluated and include: (a) endogenous (e.g. enkephalins) or exogenous (e.g. dermorphin) peptide dimer analogues (b) mixed peptidic-non-peptidic bivalent ligands and (c) dual non- Read More

The nervous and the immune systems can exchange information through opioid peptides. Furthermore, some opioid peptides can function as endogenous messengers of the immune system, and participate in an important part in the regulation of the various components of the immune response. Since the capacity of immunocytes to release and respond to opioid neuropeptide messengers is not restricted to mammalian Read More

In order to explore the possibility of preparing a high-efficiency aquaporin-based biofilter, an efficient approach for expression of membrane-bound Aquaporin Z (AqpZ) in E. coli was proposed. The AqpZ gene was amplified by means of PCR, and two expression vectors (pET28-AqpZ and pET32-AqpZ) were constructed. The channel protein of interest was synthesized in E. coli BL21(DE3)/pET32-AqpZ as an insoluble fusion protein Read More

Although the yeast Saccharomyces cerevisiae is the best exemplified single-celled eukaryote, the vast number of protein-protein interactions of integral membrane proteins of Saccharomyces cerevisiae have not been characterized by experiments. Here, based on the kernel method of Greedy Kernel Principal Component analysis plus Linear Discriminant Analysis, we identify 300 protein-protein interactions involving 189 Read More

A family of 4kDa neurotoxic peptides was purified from venoms of Phoneutria spiders. All have six cysteine residues, and low similarity with other neurotoxins. Three toxins caused moderate inhibition of L-type Ca2+ channels. The structure of toxin PRTx27C3 was modeled and compared with toxin ADO1. The importance of four residues is suggested.

SCO6571 protein from Streptomyces coelicolor A3(2) was overexpressed and purified using Rhodococcus erythropolis as an expressing host. Crystals of selenomethionine-substituted SCO6571 have been obtained by vapor diffusion method. SCO6571 crystals diffract to 2.3 Å and were found to belong to the orthorhombic space group P212121 with unit cell parameters a = 84.5, b = 171.6, c = 184.8 Å. Six molecules in t Read More

The IR-spectroscopic and structural elucidation of tetrapeptide glycyl-L-prolyl-glycyl-glycine and its hydrogensquarate was performed by employing linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic host as well as mass spectrometry. Quantum-chemical ab initio calculations were carried out in order to evaluate both the electronic structure and optical properties of the compound studied.

To investigate properties of yellow lupine cytosolic cyclophilin, an expression vector pET15CYP was constructed. The CyP cDNA (GenBank accession no.Y16088) reveals an open reading frame of 172 amino acids with the conserved tryptophan residue at position 128 and an insertion of seven amino acids spanning positions 48-54. Yellow lupine cyclophilin, purified after expression in E. coli cells, exhibits peptidyl-prolyl cis/trans i Read More

Miliin, a new thiol-dependent serine protease purified from the latex of Euphorbia milii possesses a molecular weight of 79 kDa, an isoelectric point of 4.3 and is optimally active at 60 °C in the pH range of and 7.5-11.0. Activity tests indicate that milliin is a thiol-dependent serine protease.

After several studies on prediction of mutation, we examine the effect of three sampling strategies, the sampling based on years, the sampling based on number of mutations, and the sampling based on the unpredictable portion of amino-acid pairs, on the prediction performance in H5N1 hemagglutinins. The results show that the sampling strategy does play an important role in prediction, which should be taken into accou Read More

The successful prediction of protein subcellular localization directly from protein primary sequence is useful to protein function prediction and drug discovery. In this paper, by using the concept of pseudo amino acid composition (PseAAC), the mycobacterial proteins are studied and predicted by support vector machine (SVM) and increment of diversity combined with modified Mahalanobis Discriminant (IDQD). The results of jackk Read More

In order to prevent atherosclerosis, a chimeric enzyme vaccine of AnsB-TTP-PADRE-CETPC was successfully constructed, expressed and purified to immunize New Zealand white rabbits for inducing high titers of anti-CETP antibodies to improve lipid abnormality. The protein was expressed as soluble protein in Escherichia coli and purified by anion exchange column and Sephadex G-100 size-exclusion chromatography. After im Read More

ORFans are orphan open reading frames. The numbers of ORFans are steadfastly increasing despite of the genome database increment. Characterizing ORFans is essential to fully understanding the diversity of the structure and function of proteins in nature. In this study, MPN423 from Mycoplasma pneumoniae has been cloned, expressed, purified, and crystallized. MPN423 is an orthologous ORFan whose only known ho Read More