Paul Woolley

Electrostatic interactions at charged lipid membranes. Hydrogen bonds in lipid membrane surfaces.

Hydrogen-bonded structures within lipid membrane surfaces are not disrupted by water and are of thermodynamic and therefore potential structural importance in biological systems.

A general synthetic method for enantiomerically pure ester and ether lysophospholipids

Abstract We describe a method of synthesizing virtually any lysophospholipid (i.e. phospholipid with one unsubstituted hydroxyl on the glycerol skeleton). The method is based on strategies developed earlier for the preparation of mixed-chain esters and ethers of glycerol. The products are obtained in high yield and are enantiomerically pure (racemisation

Immunoelectron microscopy of ribosomes carrying a fluorescence label in a defined position: Location of proteins S17 and L6 in the ribosome of Escherichia coli

By coupling fluorescein to a defined amino acid of a single ribosomal protein and incorporating this protein into the ribosome, we have obtained ribosomes labelled at a single, defined position. A fluorescein‐specific antibody preparation was used to locate the fluorescein residues bound to the two cysteines at positions 58 and 63 of protein S17 and to the cysteine at position 86 of protein L6. This study demonstrates the advantages which accrue from the combination of electron microscopy and fluorimetry.

Synthesis of enantiomerically pure phospholipids including phosphatidylserine and phosphatidylglycerol.

Abstract We describe a new approach to building up the head-groups of synthetic phospholipids. The approach is based upon the construction first of a completely neutral head-group, in which the phosphate bears three neutral alkyl substituents. One of these is the glycerol residue, and the second is a methyl group, which is removed cleanly at a later stage. The third determines the identity of the phospholipid to be synthesized: the range of phospholipids obtainable in this manner is very wide, and includes phosphatidylserine and phosphatidylglycerol. High-yield syntheses of these two lipids are presented here for the first time. In addition, we describe for the first time the synthesis of a potentially valuable serine-bearing precursor, N-BOC-serine t-butyl ester (BOC = t-butoxy carbonyl).

Location of protein S4 on the small ribosomal subunit of E. coli and B. stearothermophilus with protein- and hapten-specific antibodies

SummaryIn spite of considerable effort there is still serious disagreement in the literature about the question of whether epitopes of ribosomal protein S4 are accessible for antibody binding on the intact small ribosomal subunit. We have attempted to resolve this issue using three independent approaches: (i) a re-investigation of the exposure and the location of epitopes of ribosomal protein S4 on the surface of the 30S subunit and 30S core particles of the E. coli ribosome, including rigorous controls of antibody specificity, (ii) a similar investigation of protein S4 from Bacillus stearothermophilus and (iii) the labelling of residue Cys-31 of E. coli S4 with a fluorescein derivative the accessibility of which towards a fluorescein-specific antibody was demonstrated directly by fluorimetry. In each of the three cases the antigen (E. coli S4, B. stearothermophilus S4 or fluorescein) was found to reside on the small lobe.

Excluded-volume effect of inert macromolecules on the melting of nucleic acids.

It is shown on the basis of the excluded-volume effect that inert macromolecules may be expected to suppress the dissociation of double-helical nucleic acids into single helices and thus to raise the melting point of the double helix. The rise in melting temperature of the ribonucleic acid [poly(I).poly(C)] caused by dextran polymers and by poly(ethylene oxide) is described and compared with the theoretical prediction. Good agreement was found in respect of the extent of the rise in melting point and in respect of its dependence upon polymer length. An additional dependence upon the identify of the polymer was attributed to detailed effects of shape in solution.

Effect of codon shortening and the antibiotics viomycin and sparsomycin upon the behaviour of bound aminoacyl-tRNA: Decoding at the ribosomal A site

70 S ribosomes were programmed with initiator tRNA and messenger oligonucleotides AUG(U) n and AUG(C) n , where n = 1, 2 or 3. The binding of the ternary complexes [Phe‐tRNA·EF‐Tu·GTP] and [Pro‐tRNA·EF‐Tu·GTP] to the programmed ribosomes was studied. If codon—anticodon interaction is restricted to only one basepair, the ternary complex leaves the ribosome before GTP hydrolysis. Two basepairs allow hydrolysis of GTP, but the aminoacyl‐tRNA dissociates and is recycled, resulting in wastage of GTP. Three basepairs result in apparently stable binding of aminoacyl‐tRNA to the ribosome. The antibiotic sparsomycin weakens the binding by an amount roughly equivalent to one messenger base, while viomycin has the reverse effect.

Thin-layer chromatography of oligonucleotides: A device to aid the ultraviolet detection of fingerprint patterns

The observation by uv light of thin-layer fingerprint chromatograms of oligonucleotides is impeded by the use of acid eluents. A simple device is described which overcomes this difficulty.

The rate of binding of initiation factor 3 to the 30 S ribosomal subunit of escherichia coli

Various workers have studied the rates of association and dissociation of 30 S and 50 S ribosomal subunits using stopped-flow [ 1,2] and pressure-jump [3,4] techniques. The association equilibrium between these two is affected by initiation factor 3 (IF3) and an attempt has been made [4] to find out what effect the factor has on the corresponding rates. The method of detection has usually been light-scattering, which is however too insensitive to monitor the reaction between IF3 (mol. wt 20 600) and ribosomal particles (mol. wt l-3 X 106). Notwithstanding, the rate of association of IF3 with the 30 S ribosomal subunit is of interest both because this reaction is part of the initiation sequence [5] and because it may yield mechanistic information. We have prepared the fluorescent derivative dansyl-IF3; its preparation and biochemical characterisation will be detailed [6]. The fluorescence signal of the dansyl group responds to the binding of the labelled factor to the 30 S subunit and was therefore employed to investigate the rate of this association reaction. Here we present evidence that the reaction is diffusion controlled.