Protein and Peptide Letters - Volume 17, Issue 8, 2010

The notion that protein function relies on a precise 3D structure constitutes one of the central paradigms of biochemistry. According to this concept, a protein can perform its biological function(s) only after folding into a unique 3D structure, and all the information necessary for a protein to fold into this unique 3D structure (in a given environment) is encoded in the amino acid sequence. Only recently has the validity of thi Read More

Many proteins or their regions are disordered in their native, biologically active states. Bioinformatics has revealed that these proteins/regions are highly abundant in different proteomes and carry out mostly regulatory functions related to molecular recognition, signal transduction, protein-protein, and protein-nucleic acid interactions. Viruses, these “organisms at the edge of life”, have uniquely evolved to be highly adaptive Read More

Intrinsically disordered regions of significant length are present throughout eukaryotic genomes, and are particularly prevalent in viral proteins. Due to their inherent flexibility, these proteins inhabit a conformational landscape that is too complex to be described by classical structural biology. The elucidation of the role that conformational flexibility plays in molecular function will redefine our understanding of the molecular bas Read More

In this review, we summarize the main experimental data showing the abundance of structural disorder within the measles virus (MeV) nucleoprotein (N) and phosphoprotein (P), and focus on the molecular mechanisms governing the disorder-to-order transition of the intrinsically disordered C-terminal domain of MeV N (NTAIL) upon binding to the C-terminal X domain of P (XD). The functional implications of structu Read More

Rhabdoviridae are single stranded negative sense RNA viruses. The viral RNA condensed by the nucleoprotein (N), the phosphoprotein (P) and the large subunit (L) of the RNA-dependent RNA polymerase are the viral components of the transcription/replication machineries. Both P and N contain intrinsically disordered regions (IDRs) that play different roles in the virus life cycle. Here, we describe the modular organization Read More

The HIV-1 Vif protein (192 residues) is required for HIV-1 infection of many target cells. Vif overcomes the anti-viral cellular defense by antagonizing the cellular cytosine deaminase APOBEC-3G through impairing APOBEC-3G production, inhibiting its enzymatic activity and targeting it for degradation. Vif interacts with several viral and cellular molecules, particularly via its C-terminal domain (residues 100-192). The structu Read More

The type 1 Human Immunodeficiency Virus transcriptional regulator Tat is a small RNA-binding protein essential for viral gene expression and replication. The protein binds to a large number of proteins within infected cells and non-infected cells, and has been demonstrated to impact a wide variety of cellular activities. Early circular dichroism studies showed a lack of regular secondary structure in the protein whereas pr Read More

We present here our current understanding of the NS5A-D2 domain of the hepatitis C virus. Whereas this protein domain is globally unstructured as assessed by macroscopic techniques such as size exclusion chromatography, circular dichroism and homonuclear NMR spectroscopy, high resolution triple resonance spectroscopy allows the identification of a small region of residual structure. This region corresponds moreov Read More

Hepatitis C virus and related viruses in the Flaviviridae family (such as dengue virus, yellow fever virus or West Nile virus) are amongst the most important human pathogens, causing substantial morbidity and mortality worldwide. The production of viral progeny in Flaviviridae is orchestrated by the small, multifunctional core protein, which coats and condenses the viral genomic RNA during Nucleocapsid formation. In addition Read More

The human tyrosinase ectodomain has been expressed in Escherichia coli as a soluble form and purified by immobilized metal affinity column chromatography. The ectodomain exhibited tyrosinase activities toward the hydroxylation and oxidation reactions. Biochemical properties of the ectodomain appeared to be distinct from those of the human tyrosinase, although common features were retained.

There is no protective vaccine or effective drug against hepatitis C virus (HCV). Sustained virological response to INF/ribavirin treatment regimen has an efficiency of about 50%. Many patients worldwide have used traditional medicines and herbal medicine in particular. A laccase has been purified from oyster mushroom (Pleurotus ostreatus) to homogeneity by DEAE Affi-gel blue gel, CM-Sephadex G-50 and Sephadex G-100 Read More

A 66-kDa laccase, with an N-terminal sequence different from those of other mushroom laccases, was purified from fresh fruiting bodies of the edible mushroom Pleurotus cornucopiae by using affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono Q and gel filtration on Superdex 75. The procedure resulted in a 16-fold purification and a specific enzyme activity of 17.3 U mg-1. The optimum p Read More

Mouse liver cytosolic malate dehydrogenase was separated by non-denaturing two-dimensional electrophoresis and identified. Furthermore, the activity of the enzyme was preserved even after separation, electroblotting onto a membrane and staining with Ponceau S in acidic buffer solution (pH 5.1). Using the membrane-immobilized enzyme, the malic acid content was estimated by measuring absorbance changes due to th Read More

D-Alanine:D-Alanine ligase (DDl) catalyzes the formation of D-Alanine:D-Alanine dipeptide and is an essential enzyme in bacterial cell wall biosynthesis. This enzyme does not have a human ortholog, making it an attractive target for developing new antibiotic drugs. We determined the crystal structure at 2.23 Å resolution of DDl from Streptococcus mutans (SmDDl), the principal aetiological agent of human dental caries Read More

The protective effects of four osmolytes (trehalose, dimethysulfoxide, glycine and proline) on the conformational stability and aggregation of guanidine-denatured yeast alcohol dehydrogenase (YADH) have been investigated in this paper. The results show that the four osmolytes protect YADH against unfolding and inactivation by reducing ki (inactivation rate constants), increasing ΔΔGi (transition free energy changes at 2 Read More