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Physical Sciences and Mathematics

Selected Works

2012

Alpha

Articles 1 - 5 of 5

Full-Text Articles in Life Sciences

Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby Oct 2012

Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby

Stephen Blanksby

α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …


Subunit Exchange Of Polydisperse Proteins: Mass Spectrometry Reveals Consequences Of Αa-Crystallin Truncation, J. Andrew Aquilina, Justin Benesch, Lin Lin Ding, Orna Yaron, Joseph Horwitz, Carol Robinson Oct 2012

Subunit Exchange Of Polydisperse Proteins: Mass Spectrometry Reveals Consequences Of Αa-Crystallin Truncation, J. Andrew Aquilina, Justin Benesch, Lin Lin Ding, Orna Yaron, Joseph Horwitz, Carol Robinson

J. A. Aquilina

The small heat shock protein, α-crystallin, plays a key role in maintaining lens transparency by chaperoning structurally compromised proteins. This is of particular importance in the human lens, where proteins are exposed to post-translational modifications over the life-time of an individual. Here, we examine the structural and functional consequences of one particular modification of αA-crystallin involving the truncation of 5 C-terminal residues (αA1–168). Using novel mass spectrometry approaches and established biophysical techniques, we show that αA1–168 forms oligomeric assemblies with a lower average molecular mass than wild-type αA-crystallin (αAWT). Also apparent from the mass spectra of both αAWT and αA1–168 …


3-Hydroxykynurenine Oxidizes Alpha-Crystallin: Potential Role In Cataractogenesis, Roger Truscott, Andrew Aquilina, Peter Hains, Anastasia Korlimbinis Oct 2012

3-Hydroxykynurenine Oxidizes Alpha-Crystallin: Potential Role In Cataractogenesis, Roger Truscott, Andrew Aquilina, Peter Hains, Anastasia Korlimbinis

J. A. Aquilina

No abstract provided.


Evidence For Specific Subunit Distribution And Interactions In The Quaternary Structure Of Α-Crystallin, Amie M. Morris, J Andrew Aquilina Jul 2012

Evidence For Specific Subunit Distribution And Interactions In The Quaternary Structure Of Α-Crystallin, Amie M. Morris, J Andrew Aquilina

J. A. Aquilina

The quaternary structure of alpha-crystallin is dynamic, a property which has thwarted crystallographic efforts towards structural characterization. In this study, we have used collision-induced dissociation mass spectrometry to examine the architecture of the polydisperse assemblies of alpha-crystallin. For total alpha-crystallin isolated directly from fetal calf lens using size-based chromatography, the alpha B-crystallin subunit was found to be preferentially dissociated from the oligomers, despite being significantly less abundant overall than the alpha A-crystallin subunits. Furthermore, upon mixing molar equivalents of purified alpha A- and alpha B-crystallin, the levels of their dissociation were found to decrease and increase, respectively, with time. Interestingly …


Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby Feb 2012

Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby

Adam Trevitt

α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …