Protein and Peptide Letters - Volume 13, Issue 5, 2006

Research in cellular regulation is an important area of study in drug development. This special issue highlights some of the recent advances in protein and peptide chemistry that is related to cellular regulation. The functional role of a protein molecule requires an understanding of its biologic activity involved in cells. The focus is on interpretation of structural information gathered through molecular biology and various Read More

Insulin is a double-chain (designated A and B chain respectively) protein hormone containing three disulfides, while insulin is synthesized in vivo as a single-chain precursor and folded well before being released from B-cells. Although the structure and function of insulin have been well characterized, the progress in oxidative folding pathway studies of insulin has been very slow, mainly due to the difficulties brought abou Read More

In proteomics research, generation of recombinant proteins in their native, soluble form with large quantity is often a challenging task. To tackle the expression difficulties, different expression vectors with distinct affinity fusion tags, i.e. pET-43.1a (N-utilization substance A tag), pMAL-cRI (maltose binding protein tag) (MBP tag), pGEX-4T-2 (glutathione S-transferase tag), and pET-15β (hexahistidine tag) were compared for their effe Read More

The ORL1 receptors stably expressed in HEK 293 cells can utilize PTX-resistant mutants of GαoA/B to inhibit adenylyl cyclase (AC) and stimulate extracellular signal-regulated protein kinases (ERKs). However, development of AC superactivation and loss of ERK1/2 responsiveness induced by chronic activation of the ORL1 receptors remained PTXsensitive.

Site-directed mutagenesis study of the conserved residue in ferrochelatase of chironomidae showed the binding interaction of copper with histidine-60. The activities of the variants increase by > 4-fold with H60N and 2 fold with H60D. The study identifies for the first time that the highly conserved H60 is a key molecular determinant in directing a catalytically competent mode of metal binding in the active site.

Bovine pancreatic deoxyribonuclease I (bpDNase), the first DNase discovered, is the best characterized among various types of DNase. A catalytic mechanism has been suggested based on the X-ray structure of the bpDNase-octamer complex. In this review, we will focus on three aspects: 1) the distinctive functions of the two structural calcium atoms; 2) the biological functions of the two disulfides; and 3) the involvement of t Read More

Calmodulin (CaM) is a prototypical Ca2+-sensor protein that can control many important biological functions by binding to hundreds of target proteins. To gain insight into the versatility of CaM-target recognition, we have analyzed the complex structures for many types of CaM-binding peptides and some target proteins. In particular, some recently reported novel complex structures reveal that the versatile target bindin Read More

Analysis of changes in genes and protein profiles provides invaluable information to understand the activities and functions of proteins. However, their activities are further regulated by post-translational modifications, such as glycosylation and phosphorylation. Cell growth and apoptotic pathways are good examples of demonstrating the roles of phosphorylation in activation of protein cascades upon stimulation.

The formation of local structure, in short peptides has been probed by examining cleavage patterns and rates of proteolysis of designed sequences with a high tendency to form β-hairpin structures. Three model sequences which bear fluorescence donor and acceptor groups have been investigated: Dab-Gaba-Lys-Pro-Leu-Gly-Lys-Val-Xxx-Yyy-Glu-Val-Ala-Ala-Cys-Lys-NH2 ï EDANS Xxx-Yyy: Peptide 1=DPro-LPro, Peptide 2= Read More

The HIV and SIV gp41 ectodomains are extremely stable to chemical and thermal denaturation and the observed stability has been proposed to be an important thermodynamic driving force for gp41-mediated fusion of the viral and target cell membranes. The importance of the disulphide bond and surrounding residues within the HIV gp41 loop have been assayed by DSC studies of wild type and mutant HIV gp41. Based on the t Read More

Neutrophils constitute the first line of host defense against pathogens. In the present study 2-D gel electrophoresis- mass spectrometry technology was employed to analyze the human resting neutrophils proteome. One hundred and two conserved spots were subjected to peptide mass fingerprinting, yielding 22 identifications. Among the identified proteins, nine are related to the inflammatory process, two polypeptides Read More

The structural class is an important feature in characterizing the overall topological folding type of a protein or the domains therein. Prediction of protein structural classification has attracted the attention and efforts from many investigators. In this paper a novel predictor, the AdaBoost Learner, was introduced to deal with this problem. The essence of the AdaBoost Learner is that a combination of many 'weak' learning a Read More

A convenient and efficient method for the synthesis of dipeptidyl ureas and urea acids employing Osuccinimidyl-( 9H-fluoren-9-ylmethoxycarbonyl amino)methylcarbamates has been described. All the compounds, obtained in good yields, have been fully characterized by mass and NMR spectra.

Stepwise solid phase synthesis using the Fmoc chemistry is reported for a panel of 71-residue and novel unnatural chemokine analogs derived from vMIP-II. This demonstrates the feasibility of using this synthetic method to generate de novo designed protein ligand molecules to study the biology and pharmacology of chemokine receptors.

The quantitative analysis of metallochaperone proteins in biofluids (e.g. blood, liquor) may be a major prerequisite for clinical investigations concerning the structure-function relationships of biologically-active metal cofactorcontaining chaperones in protein-misfolding diseases (e.g. Alzheimer's or related diseases). For these purposes, a new state-of-the-art gel electrophoresis [quantitative preparative native continuo Read More

Escherichia coli clones expressing recombinant shiga toxin (Stx1) and its derivatives Stx1-A and Stx1-B subunits were established to release the proteins into periplasmic space. The expression was examined by SDS-PAGE to visualize the subunits. The secreted assembled subunits were extracted with polymyxin B and assessed for biological activity. The results showed that the presence of N-terminus leader sequence of t Read More

Periplasmic substrate binding proteins (PSBPs) are essential components of the bacterial periplasmic transport system, which transports a wide variety of nutrients from the periplasmic space to the cytoplasm. The glutamate/aspartate binding protein SfGlu/AspBP is a unique PSBP consisting of 279 amino acid residues. The SfGlu/AspBP gene was cloned, over-expressed, and purified by immobilized metal ion affinity chromatog Read More

The present work analyzed the tetrameric stability of the hemoglobins from the rattlesnake C. durissus terrificus using analytical gel filtration chromatography, SAXS and osmotic stress. We show that the dissociation mechanism proposed for L. miliaris hemoglobin does not apply for these hemoglobins, which constitute stable tetramers even at low concentrations.

A halophilic nucleoside diphosphate kinase from a moderate halophile, Halomonas sp. 593 (593NDK), was found to be resistant to heat treatment, as indicated by the high level of activity recovery after heating at high temperatures. This is due to reversibility of thermal unfolding, not the high melting temperature, of the protein. The highly homologous NDK from non-halophilic organism, Pseudomonas aeruginosa, showed insta Read More

Hepatocyte nuclear factor 6 (HNF-6)/OC-1, a part of liver-enriched transcription factor, controls pancreas and liver development and regulates expression of several hepatic genes. DNA-binding region of HNF-6α bound to a 14-mer DNA fragment has been crystallized by the hanging drop vapor diffusion method. The crystals belong to space group P2 with unit cell parameters of a = 73.0 Å, b = 39.0 Å, c = 106.5 Å, β= 107. Read More