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Journal Issue - Volume 19 Issue 1 (January 2010)

  • In This Issue

  • Published in Wiley Interscience on Jan 06, 2010
  • DOI: 10.1002/pro.304 (p n/a-n/a)

Abstract PpiD is a periplasmic folding helper protein of Escherichia coli. It consists of an N‐terminal helix that anchors PpiD in the inner membrane near the SecYEG translocon, followed by three periplasmic domains. The second domain (residues 264–357) shows homology to parvulin‐like prolyl isomerases. This domain is a well folded, stable protein and follows a simple two‐state folding mechanism. In its solution structure, as determined by ...

Abstract The co‐chaperone Hsp70‐Hsp90 organizing protein (HOP) plays a central role in protein folding in vivo, binding to both Hsp70 and Hsp90 and bringing them together in a functional complex. Reports in the literature concerning the oligomeric state of HOP have been inconsistent—is it a monomer, dimer, or higher order oligomer? Knowing the oligomeric state of HOP is important, because it places limits on the number and types of multiprotein...

Abstract A luciferase from the railroad worm (Phrixothrix hirtus) is the only red‐emitting bioluminescent enzyme in nature that is advantageous in multicolor luciferase assays and in bioluminescence imaging (BLI). However, it is not used widely in scientific or industrial applications because of its low activity and stability. By using site‐directed mutagenesis, we produced red‐emitting mutants with higher activity and better stability....

Abstract The Notch pathway is an intercellular signaling mechanism that plays important roles in cell fates decisions throughout the developing and adult organism. Extracellular complexation of Notch receptors with ligands ultimately results in changes in gene expression, which is regulated by the nuclear effector of the pathway, CSL (C‐promoter binding factor 1 (CBF‐1), suppressor of hairless (Su(H)), lin‐12 and glp‐1 (Lag‐1)). CSL...

Abstract A variety of proteins are capable of converting from their soluble forms into highly ordered fibrous cross‐β aggregates (amyloids). This conversion is associated with certain pathological conditions in mammals, such as Alzheimer disease, and provides a basis for the infectious or hereditary protein isoforms (prions), causing neurodegenerative disorders in mammals and controlling heritable phenotypes in yeast. The N‐proximal...

Abstract Osmolytes are small molecules that play a central role in cellular homeostasis and the stress response by maintaining protein thermodynamic stability at controlled levels. The underlying physical chemistry that describes how different osmolytes impact folding free energy is well understood, however little is known about their influence on other crucial aspects of protein behavior, such as native‐state conformational...

Abstract The apolipoprotein E family contains three major isoforms (ApoE4, E3, and E2) that are directly involved with lipoprotein metabolism and cholesterol transport. ApoE3 and apoE4 differ in only a single amino acid with an arginine in apoE4 changed to a cysteine at position 112 in apoE3. Yet only apoE4 is recognized as a risk factor for Alzheimer's disease. Here we used 19F NMR to examine structural differences between apoE4...

Abstract Alkaline phosphatases (APs) are commercially applied enzymes that catalyze the hydrolysis of phosphate monoesters by a reaction involving three active site metal ions. We have previously identified H135 as the key residue for controlling activity of the psychrophilic TAB5 AP (TAP). In this article, we describe three X‐ray crystallographic structures on TAP variants H135E and H135D in complex with a variety of metal ions....

Abstract G‐protein coupled receptors (GPCRs) are transmembrane signaling molecules, with a majority of them performing important physiological roles. β2‐Adrenergic receptor (β2‐AR) is a well‐studied GPCRs that mediates natural responses to the hormones adrenaline and noradrenaline. Analysis of the ligand‐binding region of β2‐AR using the recently solved high‐resolution crystal structures revealed a number of highly conserved amino acids that...

Abstract Published data on the characterization of unfolded proteins in dilute solutions in aqueous guanidine hydrochloride are analyzed to show that the data are not fit by either the random flight or wormlike chain models for linear chains. The analysis includes data on the intrinsic viscosity, root‐mean‐square radius of gyration, from small‐angle X‐ray scattering, and hydrodynamic radius, from the translational diffusion...

Abstract The energy transfer from the three Trp residues at positions 8, 128, and 264 within the human serum transferrin (hTF) N‐lobe to the ligand to metal charge transfer band has been investigated by monitoring changes in Trp fluorescence emission and lifetimes. The fluorescence emission from hTF N‐lobe is dominated by Trp264, as revealed by an 82% decrease in the quantum yield when this Trp residue is absent. Fluorescence...

Abstract Mycobacterium leprae recA harbors an in‐frame insertion sequence that encodes an intein homing endonuclease (PI‐MleI). Most inteins (intein endonucleases) possess two conserved LAGLIDADG (DOD) motifs at their active center. A common feature of LAGLIDADG‐type homing endonucleases is that they recognize and cleave the same or very similar DNA sequences. However, PI‐MleI is distinctive from other members of the family of...

  • A galaxy of folds

  • Vikram Alva, Michael Remmert, Andreas Biegert, Andrei N. Lupas, Johannes Söding
  • Published in Wiley Interscience on Nov 20, 2009
  • DOI: 10.1002/pro.297 (p 124-130)
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Abstract Many protein classification systems capture homologous relationships by grouping domains into families and superfamilies on the basis of sequence similarity. Superfamilies with similar 3D structures are further grouped into folds. In the absence of discernable sequence similarity, these structural similarities were long thought to have originated independently, by convergent evolution. However, the growth of databases and...

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