Peter Findeis | Bucknell University (original) (raw)

Papers by Peter Findeis

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Archives of Biochemistry and Biophysics, 2019

Plant lipoxygenases oxygenate linoleic acid to produce 13(S)-hydroperoxy-9Z,11E-octadecadienoic a... more Plant lipoxygenases oxygenate linoleic acid to produce 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid (13(S)-HPOD) or 9-hydroperoxy-10E,12Z-octadecadienoic acid (9(S)-HPOD). The manner in which these enzymes bind substrates and the mechanisms by which they control regiospecificity are uncertain. Hornung et al. (Proc. Natl. Acad. Sci. USA 96 (1999) 4192-4197) have identified an important residue, corresponding to phe-557 in soybean lipoxygenase-1 (SBLO-1). These authors proposed that large residues in this position favored binding of linoleate with the carboxylate group near the surface of the enzyme (tail-first binding), resulting in formation of 13(S)-HPOD. They also proposed that smaller residues in this position facilitate binding of linoleate in a headfirst manner with its carboxylate group interacting with a conserved arginine residue (arg-707 in SBLO-1), which leads to 9(S)-HPOD. In the present work, we have tested these proposals on SBLO-1. The F557V mutant produced 33% 9-HPOD (S:R = 87:13) from linoleic acid at pH 7.5, compared with 8% for the wild-type enzyme and 12% with the F557V,R707L double mutant. Experiments with 11(S)-deuteriolinoleic acid indicated that the 9(S)-HPOD produced by the F557V mutant involves removal of hydrogen from the pro-R position on C-11 of linoleic acid, as expected if 9(S)-HPOD results from binding in an orientation that is inverted relative to that leading to 13(S)-HPOD. The product distributions obtained by oxygenation of 10Z,13Z-nonadecadienoic acid and arachidonic acid by the F557V mutant support the hypothesis that ω6 oxygenation results from tail-first binding and ω10 oxygenation from headfirst binding. The results demonstrate that the regiospecificity of SBLO-1 can be altered by a mutation that facilitates an alternative mode of substrate binding and adds to the body of evidence that 13(S)-HPOD arises from tail-first binding.

Inorganic chemistry, Jan 4, 2018

A spirocylic diphosphite was used to generate P-metalated bimetallic complexes through protodeaur... more A spirocylic diphosphite was used to generate P-metalated bimetallic complexes through protodeauration reactions involving LAuCHBu (L = JohnPhos, BuXPhos) and metallomacrocycles through protodeauration/cyclization using BuCHAuP^PAuCHBu precursors (P^P = flexible diphosphine). While the synthesis of the bimetallic complexes followed a stepwise process, generation of the metallomacrocycles was highly complex because of a series of reversible ligand redistribution reactions. The self-assembly was monitored, and key intermediates were identified by NMR spectroscopy and high-resolution mass spectrometry. The mechanistic investigation showed that using flexible diphosphine linkers was critical to the selective synthesis of metallomacrocycles because rigid diphosphines generated intractable mixtures of linear and cyclic compounds. The X-ray structure of a 32-membered metallomacrocycle revealed that the compound crystallized in an unsymmetrical collapsed form that was held together by two s...

Journal of High Resolution Chromatography, 1984

... &#x27;Ox GCIMS chromatograms of injected/N-deme-4 ... per 450 milliseconds of each sc... more ... &#x27;Ox GCIMS chromatograms of injected/N-deme-4 ... per 450 milliseconds of each scan); hence, the disparity in relative abundance of the choline esters at picomolar concentrations as compared to relative abun-dance at higher concentrations is more statistical aberra-tion than a ...

Thesis (Ph. D.)--University of Idaho, 1983. Includes bibliographical references. [pt. 1] Age-sync... more Thesis (Ph. D.)--University of Idaho, 1983. Includes bibliographical references. [pt. 1] Age-synchronous culture of Caenorhabditis elegans: technique and applications -- [pt. 2] Determination of biogenic Quaternary ammonium compounds on fused silica capillary columns with spitless injector as a chemical reactor/pyrolysis chamber.

International Journal of Mass Spectrometry, 2015

A deprotonated 2-imidazoline-4(5)-one product ion was observed as a major fragment in the Collisi... more A deprotonated 2-imidazoline-4(5)-one product ion was observed as a major fragment in the Collision-Induced Dissociation (CID) of several dipeptides containing serine at the Cterminal and an amino acid with an alkyl substituent at the N-terminal. This fragment becomes predominant at high collision energies. The same type of product ion was seen in the CID of cyclo(GlyGly). Labeling GlySer with O-18 suggests that the fragmentation may proceed through a symmetrical intermediate such as a deprotonated diketopiperazine. Density functional theory calculations of GlySer provided a possible mechanism for the fragmentation.

ACS Macro Letters, 2012

The synthesis of cyclic polystyrene (PSt) with an alkoxyamine functionality has been accomplished... more The synthesis of cyclic polystyrene (PSt) with an alkoxyamine functionality has been accomplished by intramolecular radical coupling in the presence of a nitroso radical trap. Linear α,ω-dibrominated polystyrene, produced by the atom transfer radical polymerization (ATRP) of styrene using a dibrominated initiator, was subjected to chain-end activation via the atom transfer radical coupling (ATRC) process under pseudodilute conditions in the presence of 2-methyl-2-nitrosopropane (MNP). This radical trap-assisted, intramolecular ATRC (RTA-ATRC) produced cyclic polymers in greater than 90% yields, possessing ⟨G⟩ values in the 0.8−0.9 range as determined by gel permeation chromatography (GPC). Thermal-induced opening of the cycles, made possible by the incorporated alkoxyamine, resulted in a return to the original apparent molecular weight, further supporting the formation of cyclic polymers in the RTA-ATRC reaction. Liquid chromatography−mass spectrometry (LC-MS) provided direct confirmation of the cyclic architecture and the incorporation of the nitroso group into the macrocycle. RTA-ATRC cyclizations carried out with faster rates of polymer addition into the redox active solution and/or in the presence of a much larger excess of MNP (up to a 250:1 ratio of MNP:C−Br chain end) still yielded cyclic polymers that contained alkoxyamine functionality.

Journal of the American Chemical Society, 2001

Journal of Organometallic Chemistry, 2006

The microwave-assisted hydrophosphinylation of propargyl alcohols has been investigated using gro... more The microwave-assisted hydrophosphinylation of propargyl alcohols has been investigated using group 9 catalysts under solvent-free conditions as well as with pure water, ethyl lactate, or THF as the solvent. Reactions involving simple propargyl alcohols gave mixtures containing significant amounts of elimination products. In contrast, analogous reactions involving ethynyl steroids afforded a single species with only trace amounts of elimination products. The molecular structures of several derivatives have been determined and are discussed.

Bioorganic Chemistry, 2011

Soybean lipoxygenase-1 (SBLO-1) catalyzes the oxygenation of 1,4-dienes to produce conjugated die... more Soybean lipoxygenase-1 (SBLO-1) catalyzes the oxygenation of 1,4-dienes to produce conjugated diene hydroperoxides. The best substrates are anions of fatty acids; for example, linoleate is converted to 13(S)-hydroperoxy-9(Z),11(E)-octadecadienoate. The manner in which SBLO-1 binds substrates is uncertain. In the present work, it was found that SBLO-1 will oxygenate linoleyltrimethylammonium ion (LTMA) to give primarily13(S)-hydroperoxy-9(Z),11(E)-octadecadienyltrimethylammonium ion. The rate of this process is about the same at pH 7 and pH 9 and is about 30% of the rate observed with linoleate at pH 9. At pH 7, SBLO-1 oxygenates linoleyldimethylamine (LDMA) to give primarily 13(S)-hydroperoxy-9(Z),11(E)-octadecadienyldimethylamine. The oxygenation of LDMA occurs at about the same rate as LTMA at pH 7, but more slowly at pH 9. The results demonstrate that SBLO-1 will readily oxygenate substrates in which the carboxylate of linoleate is replaced with a cationic group, and the products of these reactions have the same stereo-and regiochemistry as the products obtained from fatty acid substrates.

Experimental Gerontology, 1983

The inclusion of mobility to an age synchrony method and the development of an inexpensive filter... more The inclusion of mobility to an age synchrony method and the development of an inexpensive filter device resulted in a natural model aging system without resorting to invasive chemical techniques. Large or small cohorts of nematodes with less than 1 °/0 offspring contamination are possible. The filter/mobility method is compared to other methods using the same strain and culture temperature. The applicability of the method is shown with a variety of parameters, and a previously reported parameter of aging in nematodes, i.e., specific gravity, is shown not to be an aging parameter of Caenorhabditis elegans,