temporary banners

 



 

Journal Issue - Volume 14 Issue 5 (May 2005)

Abstract Many of the effects exerted on protein structure, stability, and dynamics by molecular crowding and confinement in the cellular environment can be mimicked by encapsulation in polymeric matrices. We have compared the stability and unfolding kinetics of a highly fluorescent mutant of Green Fluorescent Protein, GFPmut2, in solution and in wet, nanoporous silica gels. In the absence of denaturant, encapsulation does not induce...

Abstract The six enzymes of the mevalonate pathway of isopentenyl diphosphate biosynthesis represent potential for addressing a pressing human health concern, the development of antibiotics against resistant strains of the Gram‐positive streptococci. We previously characterized the first four of the mevalonate pathway enzymes of Enterococcus faecalis, and here characterize the fifth, phosphomevalonate kinase (E.C. 2.7.4.2). E. faecalis genomic...

Abstract AT‐rich interaction domains (ARIDs) are found in a large number of eukaryotic transcription factors that regulate cell proliferation, differentiation, and development. Previously we elucidated how ARIDs recognize DNA by determining the solution structure of the Drosophila melanogaster Dead ringer protein in both its DNA‐free and ‐bound states. In order to quantitatively determine how ARIDs alter their mobility to recognize...

Abstract Using immunological approaches and mass spectrometry, five proteins associated with metallothionein‐3 in mouse brains have been identified. Metallothionein‐3 and associated proteins were isolated using immunoaffinity chromatography over immobilized anti‐mouse brain MT3 antibody. Proteins in the recovered pool were separated by SDS‐polyacrylamide gel electrophoresis, and distinct bands were excised and the proteins digested...

Abstract Conservation of function is the basic tenet of protein evolution. Conservation of key electrostatic properties is a frequently employed mechanism that leads to conserved function. In a previous report, we identified several conserved electrostatic properties in four protein families and one functionally diverse enzyme superfamily. In this report, we demonstrate the evolutionary and catalytic importance of electrostatic...

Abstract Proteolytic processing of zymogen Factor VII to Factor VIIa (FVIIa) is necessary but not sufficient for maximal proteolytic activity, which requires an additional allosteric influence induced upon binding to its cofactor tissue factor (TF). A key conformational change affecting the zymogenicity of FVIIa involves a unique three‐residue shift in the position of β‐strand B2 in their zymogen and protease forms. By selectively...

Abstract The interaction of the native Alzheimer's peptide C‐terminal fragment Aβ (29–42), and two mutants (G33A and G37A) with neutral lipid bilayers made of POPC and POPE in a 9:1 molar ratio was investigated by solid‐state NMR. This fragment and the lipid composition were selected because they represent the minimum requirement for the fusogenic activity of the Alzheimer's peptide. The chemical shifts of alanine methyl isotropic...

Abstract The two active sites of dimeric 5‐aminolevulinate synthase (ALAS), a pyridoxal 5′‐phosphate (PLP)‐dependent enzyme, are located on the subunit interface with contribution of essential amino acids from each subunit. Linking the two subunits into a single polypeptide chain dimer (2XALAS) yielded an enzyme with an approximate sevenfold greater turnover number than that of wild‐type ALAS. Spectroscopic and kinetic properties of...

Abstract The His46Arg (H46R) mutant of human copper‐zinc superoxide dismutase (SOD1) is associated with an unusual, slowly progressing form of familial amyotrophic lateral sclerosis (FALS). Here we describe in detail the crystal structures of pathogenic H46R SOD1 in the Zn‐loaded (Zn‐H46R) and metal‐free (apo‐H46R) forms. The Zn‐H46R structure demonstrates a novel zinc coordination that involves only three of the usual four...

Abstract Calcium‐ and integrin‐binding protein 1 (CIB1) is involved in the process of platelet aggregation by binding the cytoplasmic tail of the αIIb subunit of the platelet‐specific integrin αIibβ3. Although poorly understood, it is widely believed that CIB1 acts as a global signaling regulator because it is expressed in many tissues that do not express integrin αIibβ3. We report the structure of human CIB1 to a resolution of 2.3 Å,...

Abstract In recent studies, the amyloid form of recombinant prion protein (PrP) encompassing residues 89–230 (rPrP 89‐230) produced in vitro induced transmissible prion disease in mice. These studies showed that unlike “classical” PrPSc produced in vivo, the amyloid fibrils generated in vitro were more proteinase‐K sensitive. Here we demonstrate that the amyloid form contains a proteinase K‐resistant core composed only of residues 152/153–230...

Abstract The three‐dimensional crystal structure of tomato (Lycopersicon esculentum) β‐mannanase 4a (LeMAN4a) has been determined to 1.5 Å resolution. The enzyme adopts the (β/α)8 fold common to the members of glycohydrolase family GH5. The structure is comparable with those of the homologous Trichoderma reesei and Thermomonospora fusca β‐mannanases: There is a conserved three‐stranded β‐sheet located near the N terminus that stacks against the central β‐barrel ...

Abstract To better characterize the transition state for folding/unfolding and its sensitivity to environmental changes, we have run multiple molecular dynamics simulations of chymotrypsin inhibitor 2 (CI2) under varying solvent conditions and temperature. The transition state structures agree well with experiment, and are similar under all of the conditions investigated here. Increasing the temperature leads to some movement in the...

Abstract Analysis of the conformational distribution of polypeptide segments in a conformational space is the first step for understanding a principle of structural diversity of proteins. Here, we present a statistical analysis of protein local structures based on interatomic Cα distances. Using principal component analysis (PCA) on the intrasegment Cα–Cα atomic distances, the conformational space of protein segments, which we call the protein...

Abstract TonB protein of Escherichia coli couples the electrochemical potential of the cytoplasmic membrane (CM) to active transport of iron‐siderophores and vitamin B12 across the outer membrane (OM). TonB interacts with OM receptors and transduces conformationally stored energy. Energy for transport is provided by the proton motive force through ExbB and ExbD, which form a ternary complex with TonB in the CM. TonB contains three...

Page:   1 2 Next