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- Keyword
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- CMMB (12)
- Chaperone (5)
- Crystallin (5)
- Lens (4)
- Protein (4)
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- Small heat shock protein (4)
- Alpha (3)
- Human (3)
- Mass spectrometry (3)
- Aging (2)
- Alpha-crystallin (2)
- Bound (2)
- Cataract (2)
- Concentration (2)
- Cross (2)
- Filters (2)
- Free (2)
- Lenses (2)
- Linking (2)
- Mass (2)
- Normal (2)
- Proteins (2)
- Quaternary (2)
- Quaternary structure (2)
- Reveals (2)
- Spectrometry (2)
- Structure (2)
- Subunit (2)
- Truncation (2)
- ?B-crystallin (1)
Articles 1 - 23 of 23
Full-Text Articles in Social and Behavioral Sciences
Evidence For Specific Subunit Distribution And Interactions In The Quaternary Structure Of Α-Crystallin, Amie M. Morris, J. Andrew Aquilina
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 α-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 α-crystallin. For total α-crystallin isolated directly from fetal calf lens using size-based chromatography, the αB-crystallin subunit was found to be preferentially dissociated from the oligomers, despite being significantly less abundant overall than the αA-crystallin subunits. Furthermore, upon mixing molar equivalents of purified αA- and αB-crystallin, the levels of their dissociation were found to decrease and increase, respectively, with time. Interestingly though, dissociation of subunits …
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
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 …
Targeting C-Reactive Protein For The Treatment Of Cardiovascular Disease, Mark B. Pepys, Gideon M. Hirschfield, Glenys A. Tennent, J Ruth Gallimore, Melvyn C. Kahan, Vittorio Bellotti, Philip N. Hawkins, Rebecca M. Myers, Martin D. Smith, Alessandra Polara, Alexander J. A Cobb, Steven V. Ley, J. Andrew Aquilina, Carol V. Robinson, Isam Sharif, Gillian A. Gray, Caroline A. Sabin, Michelle C. Jenvey, Simon E. Kolstoe, Darren Thompson, Stephen P. Wood
Targeting C-Reactive Protein For The Treatment Of Cardiovascular Disease, Mark B. Pepys, Gideon M. Hirschfield, Glenys A. Tennent, J Ruth Gallimore, Melvyn C. Kahan, Vittorio Bellotti, Philip N. Hawkins, Rebecca M. Myers, Martin D. Smith, Alessandra Polara, Alexander J. A Cobb, Steven V. Ley, J. Andrew Aquilina, Carol V. Robinson, Isam Sharif, Gillian A. Gray, Caroline A. Sabin, Michelle C. Jenvey, Simon E. Kolstoe, Darren Thompson, Stephen P. Wood
J. A. Aquilina
Complement-mediated inflammation exacerbates the tissue injury of ischaemic necrosis in heart attacks and strokes, the most common causes of death in developed countries. Large infarct size increases immediate morbidity and mortality and, in survivors of the acute event, larger non-functional scars adversely affect long-term prognosis. There is thus an important unmet medical need for new cardioprotective and neuroprotective treatments. We have previously shown that human C-reactive protein (CRP), the classical acute-phase protein that binds to ligands exposed in damaged tissue and then activates complement1, increases myocardial and cerebral infarct size in rats subjected to coronary or cerebral artery ligation, respectively2,3. …
Understanding The Α-Crystallin Cell Membrane Conjunction, Shih-Ping Su, Jason D. Mcarthur, Michael G. Friedrich, Roger J. W Truscott, J. A. Aquilina
Understanding The Α-Crystallin Cell Membrane Conjunction, Shih-Ping Su, Jason D. Mcarthur, Michael G. Friedrich, Roger J. W Truscott, J. A. Aquilina
J. A. Aquilina
PURPOSE. It is well established that levels of soluble α-crystallin in the lens cytoplasm fall steadily with age, accompanied by a corresponding increase in the amount of membrane-bound α-crystallin. Less well understood, is the mechanism driving this age-dependent membrane association. The aim of this study was to investigate the role of the membrane and its associated proteins and peptides in the binding of α-crystallin. METHODS. Fibre cell membranes from human and bovine lenses were separated from soluble proteins by centrifugation. Membranes were stripped of associated proteins with successive aqueous, urea and alkaline solutions. Protein constituents of the respective membrane isolates …
Tandem Mass Spectrometry Reveals The Quaternary Organization Of Macromolecular Assemblies, J L Benesch, Andrew Aquilina, Brandon T. Ruotolo, Frank Sobott, C V Robinson
Tandem Mass Spectrometry Reveals The Quaternary Organization Of Macromolecular Assemblies, J L Benesch, Andrew Aquilina, Brandon T. Ruotolo, Frank Sobott, C V Robinson
J. A. Aquilina
The application of mass spectrometry (MS) to the study of progressively larger and more complex macromolecular assemblies is proving increasingly useful for structural biologists. The scope of this approach has recently been widened through the application of a tandem MS procedure. This two-step technique involves the selection of specific assemblies in the gas phase, and inducing their dissociation through collisions with argon atoms. Here we investigate the mechanism of this process and show that dissociation of subunits from a macromolecular assembly follows a sequential pathway, with the partitioning of charge between the dissociation products governed primarily by their relative surface …
3-Hydroxykynurenine Oxidizes Alpha-Crystallin: Potential Role In Cataractogenesis, Roger Truscott, Andrew Aquilina, Peter Hains, Anastasia Korlimbinis
3-Hydroxykynurenine Oxidizes Alpha-Crystallin: Potential Role In Cataractogenesis, Roger Truscott, Andrew Aquilina, Peter Hains, Anastasia Korlimbinis
J. A. Aquilina
No abstract provided.
Truncation, Cross-Linking And Interaction Of Crystallins And Intermediate Filament Proteins In The Aging Human Lens, Roger Truscott, Jason Mcarthur, Andrew Aquilina, Shi-Ping (Jim) Su
Truncation, Cross-Linking And Interaction Of Crystallins And Intermediate Filament Proteins In The Aging Human Lens, Roger Truscott, Jason Mcarthur, Andrew Aquilina, Shi-Ping (Jim) Su
J. A. Aquilina
The optical properties of the lens are dependent upon the integrity of proteins within the fiber cells. During aging, crystallins, the major intra-cellular structural proteins of the lens, aggregate and become water-insoluble. Modifications to crystallins and the lens intermediate filaments have been implicated in this phenomenon. In this study, we examined changes to, and interactions between, human lens crystallins and intermediate filament proteins in lenses from a variety of age groups (0-86 years). Among the lens-specific intermediate filament proteins, filensin was extensively cleaved in all postnatal lenses, with truncated products of various sizes being found in both the lens cortical …
Chemical Cross-Linking Of The Chloroplast Localized Small Heat-Shock Protein, Hsp21, And The Model Substrate Citrate Synthase, Emma Ahrman, W Lambert, Andrew Aquilina, C V Robinson, Cs Emanuelsson
Chemical Cross-Linking Of The Chloroplast Localized Small Heat-Shock Protein, Hsp21, And The Model Substrate Citrate Synthase, Emma Ahrman, W Lambert, Andrew Aquilina, C V Robinson, Cs Emanuelsson
J. A. Aquilina
The molecular mechanism whereby the small heat-shock protein (sHsp) chaperones interact with and prevent aggregation of other proteins is not fully understood. We have characterized the sHsp-substrate protein interaction at normal and increased temperatures utilizing a model substrate protein, citrate synthase (CS), widely used in chaperone assays, and a dodecameric plant sHsp, Hsp21, by chemical cross-linking with 3,3'-Dithiobis[sulfosuccinimidylpropionate] (DTSSP) and mass spectrometric peptide mapping. In the absence of CS, the cross-linker captured Hsp21 in dodecameric form, even at increased temperature (47 degrees C). In the presence of equimolar amounts of CS, no Hsp21 dodecamer was captured, indicating a substrate-induced Hsp21 …
Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson
Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson
J. A. Aquilina
Clusterin is the first well characterized, constitutively secreted extracellular chaperone that binds to exposed regions of hydrophobicity on non-native proteins. It may help control the folding state of extracellular proteins by targeting them for receptor-mediated endocytosis and intracellular lysosomal degradation. A notable feature of secreted clusterin is its heavy glycosylation. Although carbohydrate comprises approximately 20−25% of the total mass of the mature molecule, its function is unknown. Results from the current study demonstrate that deglycosylation of human serum clusterin had little effect on its overall secondary structure content but produced a small increase in solvent-exposed hydrophobicity and enhanced the propensity …
Protein-Bound And Free Uv Filters In Cataract Lenses. The Concentration Of Uv Filters Is Much Lower Than In Normal Lenses, Roger Truscott, Andrew Aquilina, Anastasia Korlimbinis
Protein-Bound And Free Uv Filters In Cataract Lenses. The Concentration Of Uv Filters Is Much Lower Than In Normal Lenses, Roger Truscott, Andrew Aquilina, Anastasia Korlimbinis
J. A. Aquilina
In human cataract lenses the UV filters, 3-hydroxykynurenine glucoside (3OHKG) and kynurenine (Kyn) were found to be covalently bound to proteins and the levels in the nucleus were much higher than in the cortex. The levels of the bound UV filters in cataract nuclei were much lower than those in age-matched normal lenses. 3-Hydroxykynurenine could not be detected in cataract lenses. As with normal lenses, protein-bound 3OHKG in cataract lenses was found at the highest levels followed by Kyn. Free UV filter concentrations were also markedly reduced in cataract lenses. This feature may well contribute to the lower protein-bound levels; …
The Major Toxin From The Australian Common Brown Snake Is A Hexamer With Unusual Gas-Phase Dissociation Properties, Andrew Aquilina
The Major Toxin From The Australian Common Brown Snake Is A Hexamer With Unusual Gas-Phase Dissociation Properties, Andrew Aquilina
J. A. Aquilina
Asymmetric dissociation of multiply charged proteins assemblies has been frequently reported. This phenomenon, which relies on the dissociation of one or more highly charged monomers, has been shown to provide insights into the structure and organization of large monodisperse and polydisperse assemblies. Here, the process of asymmetric dissociation is investigated using the multi-subunit protein, textilotoxin, which has unusually high structural constraints on its monomers due to multiple disulfide linkages. Initially, it is shown that, contrary to previous reports, textilotoxin is made up of 6, rather than 5 subunits. Furthermore, the hexamer exists as two isoforms, one of which is substantially …
Protein-Bound Uv Filters In Normal Human Lenses: The Concentration Of Bound Uv Filters Equals That Of Free Uv Filters In The Centre Of Older Lenses, Roger Truscott, Andrew Aquilina, Anastasia Korlimbinis
Protein-Bound Uv Filters In Normal Human Lenses: The Concentration Of Bound Uv Filters Equals That Of Free Uv Filters In The Centre Of Older Lenses, Roger Truscott, Andrew Aquilina, Anastasia Korlimbinis
J. A. Aquilina
No abstract provided.
Small Heat Shock Protein Activity Is Regulated By Variable Oligomeric Substructure, J. L. Benesch, M. Ayoub, C. V. Robinson, J. A. Aquilina
Small Heat Shock Protein Activity Is Regulated By Variable Oligomeric Substructure, J. L. Benesch, M. Ayoub, C. V. Robinson, J. A. Aquilina
J. A. Aquilina
The alpha-crystallins are members of the small heat shock protein (sHSP) family of molecular chaperones which have evolved to minimize intracellular protein aggregation, however they are also implicated in a number of protein deposition diseases. In this study we have employed novel mass spectrometry techniques to investigate the changes in quaternary structure associated with this switch from chaperone to adjuvant of aggregation. We have replicated the oligomeric rearrangements observed for in vivo disease-related modifications, without altering the protein sequence, by refolding the alpha-crystallins in vitro. This refolding results in a loss of dimeric substructure concomitant with an augmentation of substrate …
R120g Αb-Crystallin Promotes The Unfolding Of Reduced Α-Lactalbumin And Is Inherently Unstable., T. M. Treweek, A. Rekas, R. A. Lindner, Mark J. Walker, J. A. Aquilina, C. V. Robinson, J. Horwitz, M. Der Perng, R. A. Quinlan, J. A. Carver
R120g Αb-Crystallin Promotes The Unfolding Of Reduced Α-Lactalbumin And Is Inherently Unstable., T. M. Treweek, A. Rekas, R. A. Lindner, Mark J. Walker, J. A. Aquilina, C. V. Robinson, J. Horwitz, M. Der Perng, R. A. Quinlan, J. A. Carver
J. A. Aquilina
α-Crystallin is the principal lens protein which, in addition to its structural role, also acts as a molecular chaperone, to prevent aggregation and precipitation of other lens proteins. One of its two subunits, αB-crystallin, is also expressed in many non-lenticular tissues, and a natural missense mutation, R120G, has been associated with cataract and desminrelated myopathy, a disorder of skeletal muscles (Vicart et al., 1998, Nature Genet. 20:92-95). In the present study, real-time 1H NMR spectroscopy showed that the ability of R120G αB-crystallin to stabilize the partially folded, molten globule state of α- lactalbumin was significantly reduced in comparison with wild …
The Small Heat-Shock Proteins Hspb2 And Hspb3 Form Well-Defined Heterooligomers In A Unique 3 To 1 Subunit Ratio, J. Den Engelsman, S. Baros, P. Y. W. Dankers, B. Kamps, W. T. Vree Egberts, C. S. Bode, L. A. Lane, J. A. Aquilina, J. L. P. Benesch, C. V. Robinson, W. W. De Jong, W. C. Boelens
The Small Heat-Shock Proteins Hspb2 And Hspb3 Form Well-Defined Heterooligomers In A Unique 3 To 1 Subunit Ratio, J. Den Engelsman, S. Baros, P. Y. W. Dankers, B. Kamps, W. T. Vree Egberts, C. S. Bode, L. A. Lane, J. A. Aquilina, J. L. P. Benesch, C. V. Robinson, W. W. De Jong, W. C. Boelens
J. A. Aquilina
Various mammalian small heat-shock proteins (sHSPs) can interact with one another to form large polydisperse assemblies. In muscle cells, HSPB2/MKBP (myotonic dystrophy protein kinase-binding protein) and HSPB3 have been shown to form an independent complex. To date, the biochemical properties of this complex have not been thoroughly characterized. In this study, we show that recombinant HSPB2 and HSPB3 can be successfully purified from E.coli cells co-expressing both proteins. Nanoelectrospray ionization mass spectrometry and sedimentation velocity analytical ultracentrifugation analysis showed that HSPB2/B3 forms a series of well defined hetero-oligomers, consisting of 4, 8, 12, 16, 20 and 24 subunits, each maintaining …
Evidence For Specific Subunit Distribution And Interactions In The Quaternary Structure Of Α-Crystallin, Amie M. Morris, J Andrew Aquilina
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 …
Role Of Group A Streptococcus Htra In The Maturation Of Speb Protease, J. N. Cole, J. A. Aquilina, P. G. Hains, A. Henningham, K. S. Sriprakash, M. G. Caparon, V. Nizet, M. Kotb, S. J. Cordwell, S. P. Djordjevic, Mark J. Walker
Role Of Group A Streptococcus Htra In The Maturation Of Speb Protease, J. N. Cole, J. A. Aquilina, P. G. Hains, A. Henningham, K. S. Sriprakash, M. G. Caparon, V. Nizet, M. Kotb, S. J. Cordwell, S. P. Djordjevic, Mark J. Walker
J. A. Aquilina
The serine protease HtrA (DegP) of the human pathogen Streptococcus pyogenes (group A Streptococcus; GAS) is localized to the ExPortal secretory microdomain and is reportedly essential for the maturation of cysteine protease SpeB. Here we utilize HSC5 (M5 serotype) and the in-frame isogenic mutant HSC5ΔhtrA to determine whether HtrA contributes to the maturation of other GAS virulence determinants. Mutanolysin cell wall extracts and secreted proteins were arrayed by 2-DE and identified by MALDI-TOF PMF analysis. HSC5ΔhtrA had elevated levels of cell wall-associated M protein, whilst the supernatant had higher concentrations of M protein fragments and a reduced amount of mature …
Localization Of Low Molecular Weight Crystallin Peptides In The Aging Human Lens Using A Maldi Mass Spectrometry Imaging Approach, S. P. Su, Jason D. Mcarthur, J. A. Aquilina
Localization Of Low Molecular Weight Crystallin Peptides In The Aging Human Lens Using A Maldi Mass Spectrometry Imaging Approach, S. P. Su, Jason D. Mcarthur, J. A. Aquilina
J. A. Aquilina
Low molecular weight (LMW) peptides, derived from the breakdown of the major eye lens proteins, the crystallins, accumulate in the human lens with age. These LMW peptides are associated with age-related lens opacity and cataract, with some shown to inhibit the chaperone activity of α-crystallin. However, the mechanism(s) giving rise to the production of these peptides, as well as their distribution within the lens, are not well understood. In this study, we have mapped the distribution of these crystallin-derived peptides present in human lenses of different ages using matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS). Our data showed that most of …
Defining The Structural Basis Of Human Plasminogen Binding By Streptococcal Surface Enolase, Amanda J. Cork, Slobodan Jergic, Sven Hammerschmidt, Bostjan Kobe, Vijay Pancholi, Justin L.P. Benesch, Carol V, Robinson, Nicholas E. Dixon, J Andrew Aquilina, Mark J. Walker
Defining The Structural Basis Of Human Plasminogen Binding By Streptococcal Surface Enolase, Amanda J. Cork, Slobodan Jergic, Sven Hammerschmidt, Bostjan Kobe, Vijay Pancholi, Justin L.P. Benesch, Carol V, Robinson, Nicholas E. Dixon, J Andrew Aquilina, Mark J. Walker
J. A. Aquilina
The flesh-eating bacterium group A Streptococcus (GAS) binds and activates human plasminogen, promoting invasive disease. Streptococcal surface enolase (SEN), a glycolytic pathway enzyme, is an identified plasminogen receptor of GAS. Here we used mass spectrometry (MS) to confirm that GAS SEN is octameric, thereby validating in silico modeling based on the crystal structure of S. pneumoniae -enolase. Site-directed mutagenesis of surface-located lysine residues (SENK252+255A, SENK304A, SENK334A, SENK344E, SENK435L and SEN434-435) was used to examine their roles in maintaining structural integrity, enzymatic function and plasminogen binding. Structural integrity of the GAS SEN octamer was retained for all mutants except SENK344E, as …
Evidence For Specific Subunit Distribution And Interactions In The Quaternary Structure Of Α-Crystallin, Amie M. Morris, J. Andrew Aquilina
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 α-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 α-crystallin. For total α-crystallin isolated directly from fetal calf lens using size-based chromatography, the αB-crystallin subunit was found to be preferentially dissociated from the oligomers, despite being significantly less abundant overall than the αA-crystallin subunits. Furthermore, upon mixing molar equivalents of purified αA- and αB-crystallin, the levels of their dissociation were found to decrease and increase, respectively, with time. Interestingly though, dissociation of subunits …
The N-Terminal Domain Of Alphab-Crystallin Is Protected From Proteolysis By Bound Substrate, J. A. Aquilina, S. J. Watt
The N-Terminal Domain Of Alphab-Crystallin Is Protected From Proteolysis By Bound Substrate, J. A. Aquilina, S. J. Watt
J. A. Aquilina
alpha-Crystallin, a major structural protein of the lens can also function as a molecular chaperone by binding to unfolding substrate proteins. We have used a combination of limited proteolysis at low temperature, and mass spectrometry to identify the regions of alpha-crystallin directly involved in binding to the structurally compromised substrate, reduced alpha-lactalbumin. In the presence of trypsin, alpha-crystallin which had been pre-incubated with substrate showed markedly reduced proteolysis at the C-terminus compared with a control, indicating that the bound substrate restricted access of trypsin to R157, the main cleavage site. Chymotrypsin was able to cleave at residues in both the …
Mimicking Phosphorylation Of Alphab-Crystallin Affects Its Chaperone Activity, Heath W. Ecroyd, Sarah Meehan, J Horwitz, Andrew Aquilina, J L Benesch, C V Robinson, Cait Macphee, John Carver
Mimicking Phosphorylation Of Alphab-Crystallin Affects Its Chaperone Activity, Heath W. Ecroyd, Sarah Meehan, J Horwitz, Andrew Aquilina, J L Benesch, C V Robinson, Cait Macphee, John Carver
J. A. Aquilina
No abstract provided.
Glutamic Acid Residues In The C-Terminal Extension Of Hsp25 Are Critical For Structural And Functional Integrity, A. M. Morris, T. M. Treweek, J. A. Aquilina, J. A. Carver, Mark J. Walker
Glutamic Acid Residues In The C-Terminal Extension Of Hsp25 Are Critical For Structural And Functional Integrity, A. M. Morris, T. M. Treweek, J. A. Aquilina, J. A. Carver, Mark J. Walker
J. A. Aquilina
Small heat shock proteins (sHsps) are intracellular molecular chaperones that prevent the aggregation and precipitation of partially-folded and destabilized proteins. sHsps are comprised of an evolutionarily conserved region of 80-100 amino acids denoted the α-crystallin domain which is flanked by regions of variable sequence and length: the N-terminal domain and the C-terminal extension. Whilst the two domains are known to be involved in organization of the quaternary structure of sHsps and interaction with their target proteins, the role of the C-terminal extension is enigmatic. Despite the lack of sequence similarity, the C-terminal extension of mammalian sHsps is typically a short, …