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Journal Issue - Volume 1 Issue 6 (June 1992)

  • Why not protein science ?

  • Hans Neurath
  • Published in Wiley Interscience on Dec 31, 2008
  • DOI: 10.1002/pro.5560010601 (p 699-699)

Abstract Serum amyloid P component (SAP) is a decamer of 10 identical 25.5‐kDa subunits. Limited proteolysis of SAP with α‐chymotrypsin cleaves the subunit into two fragments of 18 and 7.5 kDa, although the fragments stay together in the decamer under nondenaturing conditions. Proteolysis does not occur in the presence of Ca2+ (10 mM). Cleavage with α‐chymotrypsin prevents the Ca2+‐dependent binding of SAP to zymosan extract, nucleosomes, and...

Abstract We have partially purified an 18‐kDa cytoplasmic protein from 3T3‐L1 cells, which dephosphorylates pNPP and the phosphorylated adipocyte lipid binding protein (ALBP), and have identified it by virtue of kinetic and immunological criteria as an acid phosphatase (EC 3.1.3.2). The cytoplasmic acid phosphatase was inactivated by phenylarsine oxide (PAO) (Kinact = 10 μM), and the inactivation could be reversed by the dithiol,...

Abstract We demonstrate that certain phosphoryl transfer proteins of the bacterial phosphotransferase system (PTS), the fructose‐ and mannitol‐specific IIA proteins or domains, are homologous to a class of proteins, one of which is known to affect transcription of some of the nitrogen‐regulatory σ54‐dependent operons in Klebsiella pneumoniae. The phosphorylatable histidyl residue in the homologous PTS proteins and the consensus sequence in the...

Abstract The role of electrostatic interactions in stabilization of the thrombin–hirudin complex has been investigated by means of two macroscopic approaches: the modified Tanford–Kirkwood model and the finite‐difference method for numerical solution of the Poisson–Boltzmann equations. The electrostatic potentials around the thrombin and hirudin molecules were asymmetric and complementary, and it is suggested that these fields...

Abstract A high‐precision solution structure of the elastase inhibitor eglin c was determined by NMR and distance geometry calculations. A large set of 947 nuclear Overhauser (NOE) distance constraints was identified, 417 of which were quantified from two‐dimensional NOE spectra at short mixing times. In addition, a large number of homonuclear 1H‐1H and heteronuclear 1H‐15N vicinal coupling constants were used, and constraints on 42 χ1 and 38 ϕ...

Abstract The role of two “basic patch” residues, Arg‐38 and His‐62, in the catalytic function and anion‐dependent activation of yeast 3‐phosphoglycerate kinase (PGK) was investigated by site‐directed mutagenesis. Steady‐state kinetics and NMR experiments were conducted to characterize the functional properties and structural integrity of the R38A and H62A mutants. The results of these studies, in combination with earlier mutagenesis...

Abstract In a systematic attempt to identify residues important in the folding and stability of T4 lysozyme, five amino acids within α‐helix 126–134 were substituted by alanine, either singly or in selected combinations. Together with three alanines already present in the wild‐type structure this provided a set of mutant proteins with up to eight alanines in sequence. All the variants behaved normally, suggesting that the majority...

Abstract The disulfide pairings of the two Euplotes raikovi pheromones Er‐1 and Er‐2 have been determined by chemical and mass spectrometric analyses. Cystine‐linked peptides from thermolytic digestions of the native molecules were purified by reverse‐phase high performance liquid chromatography and identified in the known sequences to make the assignments. The same pairing, Cys(I)–Cys(IV), Cys(II)–Cys(VI), and Cys(III)–Cys(V), was found in...

Abstract A liquid chromatographic stationary phase was prepared by covalently binding to the surface of microparticulate silica gel functionality (benzylsilane), which mimics the side chain of the amino acid phenylalanine. The chromatographic retentions of the N‐acetyl C‐(N′‐methyl) amides of various hydrophobic and amphiphilic amino acids on this stationary phase were measured using an aqueous mobile phase. A retention order of Gly...

Abstract Conditions for in vitro unfolding and refolding of dimeric thymidylate synthase from Lactobacillus casei were found. Ultraviolet difference and circular dichroism spectra showed that the enzyme was completely unfolded at concentrations of urea over 5.5 M. As measured by restoration of enzyme activity, refolding was accomplished when 0.5 M potassium chloride was included in the refolding mixture. Recombination of subunits from...

Abstract Protoporphyrinogen oxidase (EC 1.3.3.4) (PPO) is the penultimate enzyme of the heme biosynthetic pathway. Mouse PPO has been purified in low yield and kinetically characterized by this laboratory previously. A new more rapid purification procedure is described herein, and with this protein we detect a noncovalently bound flavin moiety. This flavin is present at approximately stoichiometric amounts in the purified enzyme and...

Abstract Based on the heavy‐atom coordinates determined by the electron microscopy for the seven main helical regions of bacteriorhodopsin with the all‐trans retinal isomer, energy optimizations were carried out for helix bundles containing the all‐trans retinal and 13‐cis retinal chromophores, respectively. A combination of simulated annealing and energy minimization was utilized during the process of energy optimization. It was...