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Journal Issue - Volume 1 Issue 9 (September 1992)

  • Things to Come

  • Hans Neurath
  • Published in Wiley Interscience on Dec 31, 2008
  • DOI: 10.1002/pro.5560010901 (p 1081-1081)

Abstract A computer algorithm is described that utilizes both Edman and mass spectrometric data for simultaneous determination of the amino acid sequences of several peptides in a mixture. Gas phase sequencing of a peptide mixture results in a list of observed amino acids for each cycle of Edman degradation, which by itself may not be informative and typically requires reanalysis following additional chromatographic steps. Tandem...

Abstract Based on recent X‐ray structural information, six site‐directed mutants of human cyclophilin A (hCyPA) involving residues in the putative active site‐H54, R55, F60, Q111, F113, and H126–have been constructed, overexpressed, and purified from Escherichia coli to homogeneity. The proteins W121A (Liu, J., Chen, C.‐M., & Walsh, C.T., 1991a, Biochemistry 30, 2306–2310), H54Q, R55A, F60A, Q111A, F113A, and H126Q were assayed for cis‐trans...

Abstract The three‐dimensional structure of an R‐state conformer of glycogen phosphorylase containing the coenzyme‐substrate analog pyridoxal‐5′‐diphosphate at the catalytic site (PLPP‐GPb) has been refined by X‐ray crystallography to a resolution of 2.87 Å. The molecule comprises four subunits of phosphorylase related by approximate 222 symmetry. Whereas the quaternary structure of R‐state PLPP‐GPb is similar to that of...

Abstract Previous crystallographic studies on glycogen phosphorylase have described the different conformational states of the protein (T and R) that represent the allosteric transition and have shown how the properties of the 5′‐phosphate group of the cofactor pyridoxal phosphate are influenced by these conformational states. The present work reports a study on glycogen phosphorylase b (GPb) complexed with a modified cofactor,...

Abstract R‐state monoclinic P21 crystals of phosphorylase have been shown to be catalytically active in the presence of an oligosaccharide primer and glucose‐1‐phosphate in 0.9 M ammonium sulfate, 10 mM β‐glycerophosphate, 0.5 mM EDTA, and 1 mM dithiothreitol, the medium in which the crystals are grown or equilibrated for crystallographic studies (Barford, D. & Johnson, L.N., 1989, Nature 360, 609–616; Barford, D., Hu, S.‐H., & Johnson,...

Abstract The preferential interactions of bovine serum albumin, lysozyme, chymotrypsinogen, ribonuclease A, and β‐lactoglobulin with polyethylene glycols (PEGs) of molecular weight 200–6,000 have been measured by dialysis equilibrium coupled with high precision densimetry. All the proteins were found to be preferentially hydrated in all the PEGs, and the magnitude of the preferential hydration increased with increasing PEG size for...

Abstract Catalysis by purified avian 3‐hydroxy‐3‐methylglutaryl‐CoA lyase is critically dependent on the reduction state of the enzyme, with less than 1% of optimal activity being observed with the air‐oxidized enzyme. The enzyme is irreversibly inactivated by sulfhydryl‐directed reagents with the rate of this inactivation being highly dependent upon the redox state of a critical cysteine. Methylation of reduced avian lyase with 1...

Abstract The crystal structure of the antigen‐binding fragment of a monoclonal antibody (8F5) that neutralizes human rhinovirus serotype 2 has been determined by X‐ray diffraction studies. Antibody 8F5, obtained by immunization with native HRV2 virions, cross‐reacts with peptides of the viral capsid protein VP2, which contribute to the neutralizing immunogenic site B in this serotype. The structure was solved by the molecular...

Abstract Kinetic intermediates in protein folding are short‐lived and therefore difficult to detect and to characterize. In the folding of polypeptide chains with incorrect isomers of Xaa‐Pro peptide bonds the final rate‐limiting transition to the native state is slow, since it is coupled to prolyl isomerization. Incorrect prolyl isomers thus act as effective traps for folding intermediates and allow their properties to be studied...

Abstract The results of two 30‐ps molecular dynamics simulations of the trp repressor and trp aporepressor proteins are presented in this paper. The simulations were obtained using the AMBER molecular mechanical force field and in both simulations a 6‐Å shell of TIP3P waters surrounded the proteins. The trp repressor protein is a DNA‐binding regulatory protein and it utilizes a helix‐turn‐helix (D helix‐turn‐E helix) motif to interact with DNA....

Abstract Although aqueous simulations with periodic boundary conditions more accurately describe protein dynamics than in vacuo simulations, these are computationally intensive for most proteins. Trp repressor dynamic simulations with a small water shell surrounding the starting model yield protein trajectories that are markedly improved over gas phase, yet computationally efficient. Explicit water in molecular dynamics simulations maintains ...

Abstract The cytoplasmic domain of the human erythrocyte membrane protein, band 3 (cdb3), contains binding sites for hemoglobin, several glycolytic enzymes, band 4.1, band 4.2, and ankyrin, and constitutes the major linkage between the membrane skeleton and the membrane. Although erythrocyte cdb3 has been partially purified from proteolyzed red blood cells, further separation of the water‐soluble 43‐kDa and 41‐kDa proteolytic...

Abstract Greatly reduced automated protein sequencing degradation times of less than 25 min with concurrent on‐line phenylthiohydantoin (PTH) derivative analysis times of less than 16 min have been achieved by using a miniaturized reaction cartridge with optimized chemical and analytical cycles. Using this method a wide range of standard and novel peptides and proteins have been sequenced with reproducibly high initial and...

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