Protein and Peptide Letters - Volume 10, Issue 1, 2003

We here describe a new strategy for the delivery of oligonucleotides to cells that is based on the use of a short peptide containing three functional units: a membrane-penetrating segment, a DNA-binding domain and a cell-localization sequence. The designed vector binds strongly to oligonucleotides and has membrane-perturbing abilities in vitro. This type of multi-functional device may be a powerful tool to achieve e Read More

In lipid bilayers and organic solvents, the hydrophobic polypeptide gramicidin adopts a number of different conformations, some of which are capable of conducting monovalent cations across phospholipid membranes. The equilibria between conformations have been shown to be influenced by factors such as lipid chain length, solvent, concentration and salt. In this study, the temperature dependence of the equilib Read More

The N-terminal part of the NS3 protein from dengue virus contains a trypsin-like serine protease responsible for processing the nonstructural region of the viral polyprotein. Enzymatic activity of the NS2B-NS3(pro) precursor incorporating a full-length NS2B cofactor of dengue virus type 2 was examined by using synthetic dodecamer peptide substrates encompassing native cleavage sequences of the NS2A/NS2B, NS2B / NS3, N Read More

An α-helical coiled-coil structure is one of the basic structural units in proteins. Hydrophilic residues at the hydrophobic positions in the coiled-coil structure play important roles in structures and functions of natural proteins. We reported here a peptide that formed a triple stranded α-helical coiled-coil showing the pH-dependent structural change. The peptide was designed to have two His residues at the hydrophobic position Read More

The newly-discovered human aspartic proteinase, napsin A was not susceptible to protein inhibitors from potato, squash or yeast but was weakly inhibited by the 17 kDa polypeptide from Ascaris lumbricoides and potently by isovaleryl and lactoyl-pepstatins. A series of synthetic inhibitors was also investigated which contained in the P1-P1' positions the dipeptide analogue statine or its phenylalanine or cyclohexylalanine homolo Read More

From the temperature dependence of fluorescence quenching kinetics, a novel temperaturesensitive structure transition was discovered in a donor-acceptor labeled peptides. Perfect agreement of related abrupt changes in a1,t1 andt2 gives strong support for the existence of this structure transition, which suggests it is possible to develop peptides that can be rapidly and reversibly switched between two structure Read More

Site-directed mutagenesis was used to examine the roles of the conserved histidine, arginine and cysteine residues in acid phosphatase from Prevotella intermedia (PiACP). The replacement of histidine and arginine residues resulted in the elimination of the PiACP activity while the cysteine mutants retained activity. These results suggest that the histidine and arginine residues are essential for catalysis.

The GFRα1 cDNA was amplified by RT-PCR from fetal rat hippocampus. The soluble recombinant GFRa1 and its mutants were obtained from an Escherichia coli expression system. The biological activity of soluble GFRα1 and its mutants were evaluated in PC12 cells. The results suggest that the central domain of GFRα1 is a crucial determinant for ligand binding. This established a solid basis for further study to find the key a Read More

The conformational stability and the folding process of α, β and Ψ bovine trypsin at pH 3.0 followed by circular dichroism (CD) and size exclusion in HPLC have been analyzed as a function of urea concentration. The thermodynamic stability for α and β are ΔG = 15.91 ± 0.28 kcal / mol, DG = 15.54 ± 2.39 kcal / mol. respectively, and Ψ trypsin is ΔG = 16.10 ± 2.51 kcal / mol. The transition curves for α, β and Ψforms suggest a Read More

Temperature and Guanidine hydrochloride induced unfolding transitions of papain at pH 2.0 are biphasic implying independent and sequential unfolding of its two domains. To determine the order of unfolding, the active site located in the interface of the domains was labeled with an environment specific fluorescent probe (1,8-IAEDANS). Unfolding of this complex relative to the free protein followed by intrinsic and ext Read More

This study revealed that the content of protein S29 in ribosomes of cancer cell line A549 was distinctly low (equivalent to about 30% of that of 2BS). The conclusion was acquired based on the ratios of spot volume of ribosomal protein S29 to that of several other ribosomal proteins (S29 / L37a, S29 / L38, S29 / S27 and S29 / S28) in the same gel plate. The possible biological roles of ribosomal protein S29 in malignant transformat Read More

Spectrophotometric profiles representing the unfolding induced by guanidine on Bothrops moojeni myotoxins-I (MjTX-I) and II (MjTX-II), Bothrops jararacussu bothropstoxin-I (BthTX-I) and Bothrops pirajai piratoxin-I (PrTX-I) were obtained and compared with those obtained with bovine ribonuclease A (RNAse) and trypsin. The molar (ε1M) and percent (ε1%) extinction coefficients were determined for the four myotoxins Read More