Orientation of Non-Native 2-Monosubstituted and 2,3-Disubstituted 1,4-Naphthoquinones in the A1 binding site of PSI and the effect on the rate of electron transfer : an electron paramagnetic resonance spectroscopy study

The proce-ss ofoxygenic photosynthesis is vital to life on Earth. the central event in photosynthesis is light induced electron transfer that converts light into energy for growth. Ofparticular significance is the membrane bound multisubunit protein known as Photosystem I (PSI). PSI is a reaction centre that is responsible for the transfer of electrons across the membrane to reduce NADP+ to NADPH. The recent publication ofa high resolution X-ray structure of PSI has shown new information about the structure, in particular the electron transfer cofactors, which allows us to study it in more detail. In PSI, the secondary acceptor is crucial for forward electron transfer. In this thesis, the effect of removing the native acceptor phylloquinone and replacing it with a series of structurally related quinones was investigated via transient electron paramagnetic resonance (EPR) experiments. The orientation of non native quinones in the binding site and their ability to function in the electron transfer process was determined. It was found that PSI will readily accept alkyl naphthoquinones and anthraquinone. Q band EPR experiments revealed that the non-native quinones are incorporated into the binding site with the same orientation of the headgroup as in the native system. X band EPR spectra and deuteration experiments indicate that monosubstituted naphthoquinones are bound to the Al site with their side group in the position occupied by the methyl group in native PSI (meta to the hydrogen bonded carbonyl oxygen). X band EPR experiments show that 2, 3- disubstituted methyl naphthoquinones are also incorporated into the Al site in the same orientation as phylloquinone, even with the presence of a halogen- or sulfur-containing side chain in the position normally occupied by the phytyl tail ofphylloquinone. The exception to this is 2-bromo-3-methyl --.- _. -. - -- - - 4 _._ _ _ - _ _ naphthoquinone which has a poorly resolved spectrum, making determination of the orientation difficuh. All of the non-native quinones studied act as efficient electron acceptors. However, forward electron transfer past the quinone could only be demonstrated for anthraquinone, which has a more negative midpoint potential than phylloquinone. In the case of anthraquinone, an increased rate of forward electron transfer compared to native PSI was found. From these results we can conclude that the rate ofelectron transfer from Al to Fx in native PSI lies in the normal region ofthe Marcus Curve.

Second Welland Canal - Book 1, Survey Map 5 - Through Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township near Port Dalhousie. Identified structures associated with the Canal include the tow path and floating tow path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old towing path, the Old Canal, two unnamed bridges traversing the Old Canal, and the bed of the Twelve Mile Creek. Local area landmarks are also identified and include streets and roads (ex. Old Road, Side Line, Road to Port Dalhousie), Samuel Wood's house, Peter Weaver's house, J. R. Tenbroeck's house, a poplar and walnut tree along the east shore, an oak and hickory tree along the west shore, and a walnut tree stump along the west shore. Properties and property owners of note are: Concession 3 Lots 21, 22, and 23, Concession 4 Lots 21, 22, and 23, Adam Gould, Samuel Wood, Peter Weaver, and John R. Tenbroeck.

Fast atom bombardment mass spectrometry of the coordination complexes of the ligand 5, 5, 7, 12, 12, 14- hexamenthyl-1, 4, 8, 11-tetraazacycloteradecane

A number of metal complexes containing the ligand 5,5,7,12,12,14-hexamethyl-l,4,8,11-tetra-azatetradecane were synthesized and analyzed using electron impact (EI) and fast atom bombardment (FAB). The FAB mass spectra were obtained in positive and negative ion mode. FAB in the positive ion mode proved to be the most successful technique for the identification of these compounds. In the majority of cases the spectra obtained using positive ion FAB were structurally informative, although not all showed molecular (M+) or quasimolecular ([M+H]+) ions. The fragmentations observed were characteristic of the ligands, and were interpreted based on the chemistry of these compounds.

Second Welland Canal - Book 1, Survey Map 13 - St. Catharines and Locks 4 and 5

Survey map of the Second Welland Canal created by the Welland Canal Company showing the Town of St. Catharines. Identified structures associated with the Canal include Lock 4, Lock House, Lock 5, Small Lock House, the towing path, and Gasometer for Canal. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include streets and roads (ex. Geneva Street, Queenston Street, and Academy Street), C. Phelps Mill and Store House, St. Catharines and Welland Canal Gas Works, William Mahony's Tannery, Cooper Shop, a barrel shed, barn, and gas tanks. Properties and property owners of note are: Concession 6 Lots 14, 14, and 16, Concession 7 Lots 14, 15, and 16, C. Phelps, R. M. Clement, Orson Phelps, R. Collier, D. P. Haynes, W. Chace, and John Soper.

Second Welland Canal - Book 3, Survey Map 1 - Canal to Chippewa Creek with Port Robinson

Survey map of the Second Welland Canal created by the Welland Canal Company showing Port Robinson and the canal to Chippewa Creek. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include streets and roads (ex. Front Street, Bridge Street, and Cross Street), the Welland railroad, Dry Dock leased to D. McFarland and Abbey, G. Jordan Tavern, D. McFarland and Co. Burnt Saw Mill, I. Pew Shop, Old Locks, New Lock, Canal to Chippewa Creek, Chippewa Creek, covered drain from dry dock, a barn and several bridges. Properties and property owners of note are: Lots 202, Broken Front lots 202 and 203, D. McFarland, and G. Jordan.