Protein and Peptide Letters - Volume 15, Issue 3, 2008

Increasing antibiotic resistance has led to an urgent need for new therapeutic approaches. Host defense peptides are known to be antimicrobial and have revealed broad immunomodulatory functions for both innate and adaptive immunity. This review will focus on the role of host defense peptides in infection and immune response and discuss its potential and limitations as a future therapeutical agent.

Proteins with the double stranded beta-helix (DSBH, also known as cupin) fold perform a diverse range of functions. In this study, Bacillus subtilis quercetinase was used as a model system to understand the conformational determinants of functional diversity within the cupin fold. Controlled proteolysis experiments revealed that this enzyme is active, thermo-stable and maintains its quaternary arrangement even after substa Read More

Cytochrome c oxidases of prion protein (PrP) gene-deficient (Prnp-/-) and Prnp+/+ mice were examined in vivo and in vitro. Non-invasive near-infrared spectra revealed that oxidation of copper and heme a+a3 in cytochrome c oxidase of Prnp-/- mice was similar to that in Prnp+/+ mice. Biochemical analysis of mitochondrial fractions also supported the results. PrP might not be involved in regulation of cytochrome c oxidase.

Intestinal trefoil factor (ITF), a member of the trefoil factor family, plays an important role in protecting the epithelial layer of the intestinal tract from damage and repairing epithelium after injury. In the present study, we expressed recombinant hITF by Picha pastoris expression system in shake flasks to 50mg/L. rhITF was purified up to 95% by ammonium sulfate precipitation, Ni-NTA affinity chromatography and ultrafiltrati Read More

The primary specificity residue of a substrate or an inhibitor, called the P1 residue, is responsible for the proper recognition by the cognate enzyme. This residue enters the S1 pocket of the enzyme and establishes contacts (up to 50%) inside the proteinase substrate cavity, strongly affecting its specificity. To analyze the influence on bovine α-chymotrypsin substrate activity, aromatic non-proteinogenic amino acid resi Read More

Natural surfactin is a mixture of cyclic lipopeptides built from variants of a heptapeptide and a ß-hydroxy fatty acid. A biosurfactant-producing strain, Bacillus Sabtilis HSO121, was isolated from the production water of an oil field. The strain was able to produce eight surfactin isoforms which have been isolated by acid-precipitation followed by extraction into methanol. A novel procedure for the purification of surfactin was ac Read More

Erythrina velutina vicilin, EvV, is a dimeric glycoprotein with Mr of 124.6 kDa. EvV was tested for anti-insect activity against bean bruchid larvae. EvV had LD50 of 0.10% and ED50 of 0.14% for Z. subfasciatus and LD50 of 0.26% and ED50 of 0.19% for C. maculatus. EvV was not digested by bean larvae enzymes until 12 h of incubation, and at 24 h EvV was more resistant to Z. subfasciatus enzymes.

In the present study, seven novel dimeric analogues of endomorphin-2 with longer spacers were designed and synthesized. Through dimerization, their affinity for δ-opioid receptor was mostly increased, especially the δ-opioid receptor preferred dimeric analogue, DEM12. The results were confirmed by the in vitro bioassay. The structure-activity relationships were also discussed.

Plant profilins form a well-known panallergen family responsible for cross-sensitization between plant foods and pollens. We sought to map T and B-cell epitopes on the Iranian Crocus sativus profilin by bioinformatics tools. The predicted peptides are useful for further vaccine development.

Protein subcellular localization, which tells where a protein resides in a cell, is an important characteristic of a protein, and relates closely to the function of proteins. The prediction of their subcellular localization plays an important role in the prediction of protein function, genome annotation and drug design. Therefore, it is an important and challenging role to predict subcellular localization using bio-informatics approach. In t Read More

A computer-aided docking study was carried out to quickly clarify the binding structure of the ligand-receptor complex between bisphenol A (BPA), a well-known endocrine disruptor, and estrogen-related receptor γ (ERRγ). The resulting complex indicated that BPA binds to the ligand-binding pocket of ERRγ without any disruptions of the activation conformation.

Phytases play important roles in agricultural and feed industries. In this study, the stability of a beta-propeller phytase, PhyL, from Bacillus licheniformis was successfully improved by introducing Xaa→Pro and Gly→Ala substitutions at consensus positions. Our results suggest that Gly→Ala substitution is a more promising strategy to improve protein stability.

G pretein coupled-receptors (GPCR) have been shown to form heterodimers or heterooligomers with various biochemical and/or pharmacological activity that are distinct from those of the corresponding monomers or homomers. Recent in vitro and in vivo experimental data have also shown novel functional roles of several orphan GPCRs as modulatory units of heterodimers and potentials for development of heterodimer-sele Read More

As a part of our spectroscopic and structural elucidation of small peptides, their salts and metal complexes, the polarized IR-spectroscopic and structural elucidation of the protonated form of glycyl-L-phenylalanyl-glycine as hydrochloride monohydrate (H-Gly-Phe-Gly-OHxHClxH2O) is reported. The obtained structure of the protonated tripeptide is supported by quantum chemical ab initio calculations at UHF level of the Read More

Several autoantibodies found in RA are directed to epitopes in citrullinated proteins. One of them is anti modified citrullinated vimentin (Anti-MCV). We tested the value a newly developed ELISA for the detection of antibodies againts a genetically modified citrullinated vimentin (anti-MCV) in comparison with an anti-CCP based ELISA system for the diagnosis of RA. Thirty-five patients with RA (mean age; 42.6 ± 10.87 years, m Read More

Hemoglobin (Hb) is a tetrameric protein, which contains four heme prosthetic groups, and each one is associated with a polypeptide chain. Herein, we report the rabbit hemoglobin which has intrinsically high oxygen affinity and possess highest sequence identity with human hemoglobin. The purified hemoglobin has been tried to crystallize in different crystallization conditions owing to its formation of various crystal systems. T Read More