Preliminary Studies on the Aggregation Process of Alpha-Crystallin

Doss, Ellen W.; Ward, Kristen M.; Koretz, Jane F.

doi:10.1006/exer.1997.0337

Cited by 17 publications

(24 citation statements)

References 43 publications

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“…In the absence of BSA, the increase in the amount of tetramer as a function of concentration ( fig. 3a) is almost identical to that observed previously [16], as is the formation of the high molecular weight form ( fig. 3b).…”

Section: Fplc Experiments Assessingsupporting

confidence: 90%

“…Shoulders, which initiated peaks of the BSA species, were observed at approximately 17 and 31 min, respectively. Results for the calibration of concentration and peak area and for the calibration of sample concentration and appearance of certain characteristic molecular weight species of ·-crystallin are consistent with those found in Doss et al [16]. When a sample of an incubation mixture between ·-crystallin and BSA is analyzed by gel filtration chromatography, peaks eluting from the two columns, for ·-crystallin and BSA, are close together.…”

Section: Separation and Characterization Of Protein Species With Gel supporting

confidence: 87%

“…As noted by Doss et al [16], among others, the native particle of ·-crystallin, once attained, appears to be kinetically trapped in the form; dilution of such solutions to well below the CMC for the native form does not result in a reversal of the association process. If the protein shed by the lens into the aqueous humor is already in the native form, it is unlikely that it can interact with the trabecular meshwork surfaces in hydrophobic interactions.…”

Section: Discussionmentioning

confidence: 79%

“…Because, as reviewed in the Introduction, ·-crystallin appears to exhibit at least some of the characteristics required for a causative agent, Russell et al [1] used it as an example in their presentation. Since the 'fines' hypothesis was first presented, Doss et al [16] have characterized the concentration-dependent formation of the high molecular weight ·-crystallin aggregate, as well as the size of the smaller oligomers from which it is formed. That analysis has served as the basis for the present study of the interaction between bovine ·-crystallin and bovine serum albumin.…”

Section: Discussionmentioning

confidence: 99%

“…Experimental results by Radlick and Koretz [14] and Carver et al [15] support the hypotheses that the subunit of ·-crystallin is amphipathic, and that these subunits nonspecifically aggregate to form micelles, depending on initial protein and critical micelle concentrations. More recently, Doss et al [16] have shown that the concentration-dependent formation of native-sized ·-crystallin aggregates proceeds through a series of intermediates (monomer/ dimer } tetramer → 'native') that continue to exist in conjunction with the native form at and above the CMC. It should be noted that, in the monomeric/dimeric state, amphipathic ·-crystallin molecules have their hydrophobic regions exposed.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Investigation of the ‘Fines’ Hypothesis of Primary Open-Angle Glaucoma: The Possible Role of Alpha-Crystallin

Doss

Ward²,

Koretz³

1998

Ophthalmic Res

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Primary open-angle glaucoma is a disease caused by an increase in intraocular pressure due to a decreased facility of outflow of aqueous humor through the trabecular meshwork. The etiology of primary open-angle glaucoma is currently unknown, but it has been suggested that one possible mechanism may be the obstruction of flow through the trabecular meshwork by small macromolecules, analogous to the effect of ‘fines’ in column chromatography. One such candidate is α-crystallin, a lens protein which may be released into the aqueous humor from lens fiber cells at concentrations below that necessary for the formation of the native aggregate. Results of in vitro binding experiments indicate that α-crystallin and serum albumin, which is secreted at the anterior root of the iris and is believed to act as a protein escort through the trabecular meshwork in mammalian eyes, will interact at concentrations of α-crystallin up to the critical micelle concentration for α-crystallin (3.5–5 mg/ml, or 0.18–0.25 mM). There is little interaction at or above this concentration. This binding could serve the necessary function of preventing interactions between α-crystallin monomers or small aggregates and hydrophobic surfaces within the trabecular meshwork. Since, however, the interaction between the two proteins is not extremely strong, the accumulation of unbound α-crystallin monomers and/or dimers could contribute to the development of primary open-angle glaucoma.

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Section: Fplc Experiments Assessingsupporting

confidence: 90%

Section: Separation and Characterization Of Protein Species With Gel supporting

confidence: 87%

Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Investigation of the ‘Fines’ Hypothesis of Primary Open-Angle Glaucoma: The Possible Role of Alpha-Crystallin

Doss

Ward²,

Koretz³

1998

Ophthalmic Res

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Obtaining protein solvent accessible surface area when structural data is unavailable using osmotic pressure

Bride

Rodgers

2011

AIChE Journal

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Here, we provide an algorithm that predicts solvent accessible surface area (SASA) using concentrated solution osmotic pressure data. Sheep hemoglobin monomer and β‐lactoglobulin are used for verification. Additionally, SASA for structurally unknown calf lens α‐crystallin aggregate is predicted. Using osmotic pressure data, the predicted SASA value for sheep hemoglobin, 22,398 ± 1,244 Å2, was in excellent agreement with computational model predictions (24,304 Å2‐26,100 Å2). Similarly, predicted SASA values for bovine β‐lactoglobulin in pH solutions of pH 5.1, 6.0, and 8.0, were 5,765 ± 1,031 Å2, 6,656 ± 1,082 Å2, and 9,141 ± 1,060 Å2, respectively, were in good agreement with the computationally determined SASA value (7,500 Å2–8,628 Å2). Predicted SASA for the aggregate of calf lens α‐crystallin (800 kDa) was found to be 417,691 ± 16,790 Å2. These results illustrate that this novel method can provide an important experimental alternative in estimating SASA for proteins and, possibly, their complexes in solution. © 2011 American Institute of Chemical Engineers AIChE J, 2012

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Thermal and acid denaturation of bovine lens α‐crystallin

et al. 2011

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The chaperone-like protein α-crystallin is a ∼35 subunit hetero-oligomer consisting of αA and αB subunits in a 3:1 molar ratio and has the function of maintaining eye lens transparency. We studied the thermal denaturation of α-crystallin by differential scanning calorimetry (DSC), circular dichroism (CD), and dynamic light scattering (DLS) as a function of pH. Our results show that between pH 7 and 10 the protein undergoes a reversible thermal transition. However, the thermodynamic parameters obtained by DSC are inconsistent with the complete denaturation of an oligomeric protein of the size of α-crystallin. Accordingly, the CD data suggest the presence of extensive residual secondary structure above the transition temperature. Within the pH range from 4 to 7 the increased aggregation propensity around the isoelectric point (pI ∼ 6) precludes observation of a thermal transition. As pH decreases below 4 the protein undergoes a substantial unfolding. The secondary structure content of the acid-denatured state shows little sensitivity to heating. We propose that the thermal transition above pH 7 and the acid-induced transition at ambient temperature result in predominant denaturation of the αB subunit. Although the extent of denaturation of the αA subunit cannot be estimated from the current data, the existence of a native-like conformation is suggested by the preserved association of the subunits and the chaperone-like activity. A key difference between the thermal and the acid denaturation is that the latter is accompanied by dissociation of αB subunits from the remaining αA-oligomer, as supported by DLS studies.

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Preliminary Studies on the Aggregation Process of Alpha-Crystallin

Cited by 17 publications

References 43 publications

Investigation of the ‘Fines’ Hypothesis of Primary Open-Angle Glaucoma: The Possible Role of Alpha-Crystallin

Investigation of the ‘Fines’ Hypothesis of Primary Open-Angle Glaucoma: The Possible Role of Alpha-Crystallin

Obtaining protein solvent accessible surface area when structural data is unavailable using osmotic pressure

Thermal and acid denaturation of bovine lens α‐crystallin

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