temporary banners

 



 

Journal Issue - Volume 13 Issue 9 (September 2004)

Abstract Streptococcal pyrogenic exotoxin A (SpeA1) is a bacterial superantigen associated with scarlet fever and streptococcal toxic shock syndrome (STSS). SpeA1 is found in both monomeric and dimeric forms, and previous work suggested that the dimer results from an intermolecular disulfide bond between the cysteines at positions 90 of each monomer. Here, we present the crystal structure of the dimeric form of SpeA1. The toxin...

Abstract The processive β‐strands and turns of a polypeptide parallel β‐helix represent one of the topologically simplest β‐sheet folds. The three subunits of the tailspike adhesin of phage P22 each contain 13 rungs of a parallel β‐helix followed by an interdigitated section of triple‐stranded β‐helix. Long stacks of hydrophobic residues dominate the elongated buried core of these two β‐helix domains and extend into the core of the...

Abstract Nonspecific lipid transfer proteins (nsLTPs) facilitate the transfer of phospholipids, glycolipids, fatty acids and steroids between membranes, with wide‐ranging binding affinities. Three crystal structures of rice nsLTP1 from Oryza sativa, complexed with myristic (MYR), palmitic (PAL) or stearic acid (STE) were determined. The overall structures of the rice nsLTP1 complexes belong to the four‐helix bundle folding with a long...

Abstract The microsomal (Mc) and mitochondrial (OM) isoforms of mammalian cytochrome b5 are the products of different genes, which likely arose via duplication of a primordial gene and subsequent functional divergence. Despite sharing essentially identical folds, heme‐polypeptide interactions are stronger in OM b5s than in Mc b5s due to the presence of two conserved patches of hydrophobic amino acid side chains in the OM heme binding pockets. This ...

Abstract Arsenic is a ubiquitous environmental toxic metal. Consequently, organisms detoxify arsenate by reduction to arsenite, which is then excreted or sequestered. The ArsC arsenate reductase from Escherichia coli plasmid R773, the best characterized arsenic‐modifying enzyme, has a catalytic cysteine, Cys 12, in the active site, surrounded by an arginine triad composed of Arg 60, Arg 94, and Arg 107. During the reaction cycle, the native...

Abstract Pit viper venoms contain a number of serine proteinases that exhibit one or more thrombin‐like activities on fibrinogen and platelets, this being the case for the kinin‐releasing and fibrinogen‐clotting KN‐BJ from the venom of Bothrops jararaca. A three‐dimensional structural model of the KN‐BJ2 serine proteinase was built by homology modeling using the snake venom plasminogen activator TSV‐PA as a major template and porcine kallikrein...

Abstract Rad23 proteins are involved both in the ubiquitin‐proteasome pathway and in nucleotide excision repair (NER), but the relationship between these two pathways is not yet understood. The two human homologs of Rad23, hHR23A and B, are functionally redundant in NER and interact with xeroderma pigmentosum complementation group C (XPC) protein. The XPC–hHR23 complex is responsible for the specific recognition of damaged DNA,...

  • Solution structure of cis/trans isomerases

  • Angelika Kühlewein, Georg Voll, Birte Hernandez Alvarez, Horst Kessler, Gunter Fischer, Jens‐Ulrich Rahfeld, Gerd Gemmecker
  • Published in Wiley Interscience on Jan 01, 2009
  • DOI: 10.1110/ps.04756704 (p 2378-2387)

Abstract E. coli Par10 is a peptidyl‐prolyl cis/trans isomerase (PPIase) from Escherichia coli catalyzing the isomerization of Xaa‐Pro bonds in oligopeptides with a broad substrate specificity. The structure of E. coli Par10 has been determined by multidimensional solution‐state NMR spectroscopy based on 1207 conformational constraints (1067 NOE‐derived distances, 42 vicinal coupling‐constant restraints, 30 hydrogen‐bond restraints, and 68 ϕ/ψ restraints...

Abstract Laccases and other four‐copper oxidases are usually constructed of three domains: Domains one and three house the copper sites, and the second domain often helps form a substrate‐binding cleft. In contrast to this arrangement, the genome of Streptomyces coelicolor was found to encode a small, four‐copper oxidase that lacks the second domain. This protein is representative of a new family of enzymes—the two‐domain laccases. Disruption...

Abstract Carbamoyl phosphate synthetase plays a key role in both pyrimidine and arginine biosynthesis by catalyzing the production of carbamoyl phosphate from one molecule of bicarbonate, two molecules of MgATP, and one molecule of glutamine. The enzyme from Escherichia coli consists of two polypeptide chains referred to as the small and large subunits, which contain a total of three separate active sites that are connected by an...

Abstract Decay‐accelerating factor (DAF, CD55) is a glycophosphatidyl inositol‐anchored glycoprotein that regulates the activity of C3 and C5 convertases. In addition to understanding the mechanism of complement inhibition by DAF through structural studies, there is also an interest in the possible therapeutic potential of the molecule. In this report we describe the cloning, expression in Escherichia coli, isolation and...

Abstract The Escherichia coli protein HU functions as an architectural DNA‐binding protein by facilitating DNA looping or bending to form multiprotein complexes. Although HU does not recognize a specific DNA sequence, site‐specific binding to a number of discontinuous, looped, or bent DNA substrates has been observed. In this study UV resonance Raman (UVRR) spectroscopy is used to identify structural elements associated with low‐...

Abstract To investigate the folding behavior of amyloidogenic proteins under extreme temperatures, the kinetics of fibrillation and accompanying secondary structure transitions of bovine insulin were studied for temperatures ranging up to 140°C. The presence of extreme heat stress had traditionally been associated with irreversible denaturation of protein while the initial steps of such a denaturation process may be common with a...

Abstract Dystroglycan (DG) is an adhesion complex, expressed in a wide variety of tissues, formed by an extracellular and a transmembrane subunit, α‐DG and β‐DG, respectively, interacting noncovalently. Recently, we have shown that the recombinant ectodomain of β‐DG, β‐DG(654–750), behaves as a natively unfolded protein, as it is able to bind the C‐terminal domain of α‐DG, while not displaying a defined structural organization. We...

Abstract We present the results of an exact analysis of a model energy landscape of a protein to clarify the idea of the transition state and the physical meaning of the ϕ values determined in protein engineering experiments. We benchmark our findings to various theoretical approaches proposed in the literature for the identification and characterization of the transition state.

Page:   1 2 Next