Several algorithms have been described in the literature for protein identification by searching a sequence database using mass spectrometry data. In some approaches, the experimental data are peptide molecular weights from the digestion of a protein by an enzyme. Other approaches use tandem mass spectrometry (MS/MS) data from one or more peptides. Still others combine mass data with amino acid sequence data. We present results from a new computer program, Mascot, which integrates all three types of search. The scoring algorithm is probability based, which has a number of advantages: (i) A simple rule can be used to judge whether a result is significant or not. This is particularly useful in guarding against false positives. (ii) Scores can be compared with those from other types of search, such as sequence homology. (iii) Search parameters can be readily optimised by iteration. The strengths and limitations of probability-based scoring are discussed, particularly in the context of high throughput, fully automated protein identification.

Probability-based protein identification by searching sequence databases using mass spectrometry data.

http://nhjy.hzau.edu.cn/kech/ssyy/pdf/drought/4.PDF

Photosynthesis under drought and salt stress: regulation mechanisms from whole plant to cell

The three-dimensional structure of acetylcholinesterase from Torpedo californica electric organ has been determined by x-ray analysis to 2.8 angstrom resolution. The form crystallized is the glycolipid-anchored homodimer that was purified subsequent to solubilization with a bacterial phosphatidylinositol-specific phospholipase C. The enzyme monomer is an alpha/beta protein that contains 537 amino acids. It consists of a 12-stranded mixed beta sheet surrounded by 14 alpha helices and bears a striking resemblance to several hydrolase structures including dienelactone hydrolase, serine carboxypeptidase-II, three neutral lipases, and haloalkane dehalogenase. The active site is unusual because it contains Glu, not Asp, in the Ser-His-acid catalytic triad and because the relation of the triad to the rest of the protein approximates a mirror image of that seen in the serine proteases. Furthermore, the active site lies near the bottom of a deep and narrow gorge that reaches halfway into the protein. Modeling of acetylcholine binding to the enzyme suggests that the quaternary ammonium ion is bound not to a negatively charged "anionic" site, but rather to some of the 14 aromatic residues that line the gorge.

https://science.sciencemag.org/content/sci/253/5022/872.full.pdf

Atomic structure of acetylcholinesterase from Torpedo californica: a prototypic acetylcholine-binding protein

Synthesis, structure and properties of polyhydroxyalkanoates: biological polyesters

ROS signaling: the new wave?

Synthesis of fatty acids de novo is required for photosynthetic acclimation of Synechocystis sp. PCC 6803 to high temperature.

Diazaborine and isoniazid are, at first sight, unrelated anti-bacterial agents that inhibit the enoyl-ACP reductase (ENR) of Escherichia coli and Mycobacterium tuberculosis respectively. The crystal structures of these enzymes including that of the diazaborine-inhibited E. coli ENR have been obtained at high resolution. Site-directed mutagenesis was used to study the importance of amino acid residues in diazaborine susceptibility and enzyme function. The results show that drug binding and inhibition require the presence of a glycine residue at position 93 of E. coli ENR or at the structurally equivalent position in the plant homologue, which is naturally resistant to the drug. The data confirm the hypothesis that any amino acid side-chain other than hydrogen at this position within the three-dimensional structure of these enzymes will affect diazaborine resistance by encroaching into the drug binding site. Substitutions of Gly-93 by amino acids with small side-chains, such as serine, alanine, cysteine and valine, hardly affected the catalytic parameters and rendered the bacterial host resistant to the drug. Larger amino acid side-chains, such as that of arginine, histidine, lysine and glutamine, completely inactivated the activity of the enzyme.

Molecular genetic analysis of enoyl‐acyl carrier protein reductase inhibition by diazaborine

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2880%2980027-5

Selective purification of plant proteins which co-polymerise with mammalian microtubules.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793%2898%2901055-2

cDNA cloning of Brassica napus malonyl‐CoA:ACP transacylase (MCAT) (fab D) and complementation of an E. coli MCAT mutant

It has been demonstrated that conjugated linoleic acid isomers with the first double bond in position 9 (cis) or 10 (trans), added exogenously, can be desaturated in position 6 by the cyanobacterium Spirulina platensis . The metabolites, 6-cis, 9-cis, 11-trans-octadecatrienoic and 6-cis,10-trans,12-cis-octadecatrienoic acids, which have not previously been characterized, were isolated by a combination of chromatographic techniques and the structures were confirmed by gas chromatography-mass spectrometry in the form of picolinyl ester and dimethyloxazoline derivatives.

Antoni R. Slabas

Papers

Synthesis of fatty acids de novo is required for photosynthetic acclimation of Synechocystis sp. PCC 6803 to high temperature.

Molecular genetic analysis of enoyl‐acyl carrier protein reductase inhibition by diazaborine

Selective purification of plant proteins which co-polymerise with mammalian microtubules.

cDNA cloning of Brassica napus malonyl‐CoA:ACP transacylase (MCAT) (fab D) and complementation of an E. coli MCAT mutant

Conjugated fatty acids and related compounds