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Hsueh SS, Wang SS(S, Chen SH, Wang CL, Wu W(J, Lin TH. Insights to Human γD-Crystallin Unfolding by NMR Spectroscopy and Molecular Dynamics Simulations. Int J Mol Sci 2022; 23:ijms23031591. [PMID: 35163513 PMCID: PMC8836049 DOI: 10.3390/ijms23031591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Abstract
Human γD-crystallin (HGDC) is an abundant lens protein residing in the nucleus of the human lens. Aggregation of this and other structural proteins within the lens leads to the development of cataract. Much has been explored on the stability and aggregation of HGDC and where detailed investigation at the atomic resolution was needed, the X-ray structure was used as an initial starting conformer for molecular modeling. In this study, we implemented NMR-solution HGDC structures as starting conformers for molecular dynamics simulations to provide the missing pieces of the puzzle on the very early stages of HGDC unfolding leading up to the domain swap theories proposed by past studies. The high-resolution details of the conformational dynamics also revealed additional insights to possible early intervention for cataractogenesis.
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Affiliation(s)
- Shu-Shun Hsueh
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan; (S.-S.H.); (S.-S.W.); (S.-H.C.)
| | - S.-S. (Steven) Wang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan; (S.-S.H.); (S.-S.W.); (S.-H.C.)
| | - Shu-Han Chen
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan; (S.-S.H.); (S.-S.W.); (S.-H.C.)
| | - Chia-Lin Wang
- Laboratory of Nuclear Magnetic Resonance, Medical Research Department, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - W. (Josephine) Wu
- Department of Optometry, Yuanpei University of Medical Technology, Hsinchu City 30015, Taiwan
- Correspondence: (J.W.W.); (T.-H.L.); Tel.: +886-3-538-1183 (ext. 8608) (W.W.); +886-2-28712121 (ext. 2703) (T.-H.L.)
| | - Ta-Hsien Lin
- Laboratory of Nuclear Magnetic Resonance, Medical Research Department, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
- Correspondence: (J.W.W.); (T.-H.L.); Tel.: +886-3-538-1183 (ext. 8608) (W.W.); +886-2-28712121 (ext. 2703) (T.-H.L.)
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Rocha MA, Sprague-Piercy MA, Kwok AO, Roskamp KW, Martin RW. Chemical Properties Determine Solubility and Stability in βγ-Crystallins of the Eye Lens. Chembiochem 2021; 22:1329-1346. [PMID: 33569867 PMCID: PMC8052307 DOI: 10.1002/cbic.202000739] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/17/2020] [Indexed: 11/10/2022]
Abstract
βγ-Crystallins are the primary structural and refractive proteins found in the vertebrate eye lens. Because crystallins are not replaced after early eye development, their solubility and stability must be maintained for a lifetime, which is even more remarkable given the high protein concentration in the lens. Aggregation of crystallins caused by mutations or post-translational modifications can reduce crystallin protein stability and alter intermolecular interactions. Common post-translational modifications that can cause age-related cataracts include deamidation, oxidation, and tryptophan derivatization. Metal ion binding can also trigger reduced crystallin solubility through a variety of mechanisms. Interprotein interactions are critical to maintaining lens transparency: crystallins can undergo domain swapping, disulfide bonding, and liquid-liquid phase separation, all of which can cause opacity depending on the context. Important experimental techniques for assessing crystallin conformation in the absence of a high-resolution structure include dye-binding assays, circular dichroism, fluorescence, light scattering, and transition metal FRET.
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Affiliation(s)
- Megan A. Rocha
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
| | - Marc A. Sprague-Piercy
- Department of Molecular Biology and Biochemistry, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697-2525
| | - Ashley O. Kwok
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
| | - Kyle W. Roskamp
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
| | - Rachel W. Martin
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
- Department of Molecular Biology and Biochemistry, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697-2525
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Wolffsohn JS, Davies LN. Presbyopia: Effectiveness of correction strategies. Prog Retin Eye Res 2018; 68:124-143. [PMID: 30244049 DOI: 10.1016/j.preteyeres.2018.09.004] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 01/04/2023]
Abstract
Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.
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Affiliation(s)
- James S Wolffsohn
- Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK.
| | - Leon N Davies
- Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK
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Khan JM, Khan MS, Alsenaidy MA, Ahmed A, Sen P, Oves M, Al-Shabib NA, Khan RH. Sodium louroyl sarcosinate (sarkosyl) modulate amyloid fibril formation in hen egg white lysozyme (HEWL) at alkaline pH: a molecular insight study. J Biomol Struct Dyn 2017; 36:1550-1565. [DOI: 10.1080/07391102.2017.1329097] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Javed Masood Khan
- Faculty of Food and Agricultural Sciences, Department of Food Science and Nutrition, King Saud University, 2460 Riyadh 11451, Saudi Arabia
| | - Mohd Shahnawaz Khan
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | | | - Anwar Ahmed
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Priyankar Sen
- Centre for Bioseparation Technology, VIT University, Vellore 632014, India
| | - Mohammad Oves
- Center of Excellence in Enviromental Studies, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Nasser Abdulatif Al-Shabib
- Faculty of Food and Agricultural Sciences, Department of Food Science and Nutrition, King Saud University, 2460 Riyadh 11451, Saudi Arabia
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
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Cheng MH, Tam CN, Choy KW, Tsang WH, Tsang SL, Pang CP, Song YQ, Sham MH. A γA-Crystallin Mouse Mutant Secc with Small Eye, Cataract and Closed Eyelid. PLoS One 2016; 11:e0160691. [PMID: 27513760 PMCID: PMC4981419 DOI: 10.1371/journal.pone.0160691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/23/2016] [Indexed: 11/18/2022] Open
Abstract
Cataract is the most common cause of visual loss in humans. A spontaneously occurred, autosomal dominant mouse mutant Secc, which displayed combined features of small eye, cataract and closed eyelid was discovered in our laboratory. In this study, we identified the mutation and characterized the cataract phenotype of this novel Secc mutant. The Secc mutant mice have eyelids that remain half-closed throughout their life. The mutant lens has a significant reduction in size and with opaque spots clustered in the centre. Histological analysis showed that in the core region of the mutant lens, the fiber cells were disorganized and clefts and vacuoles were observed. The cataract phenotype was evident from new born stage. We identified the Secc mutation by linkage analysis using whole genome microsatellite markers and SNP markers. The Secc locus was mapped at chromosome 1 flanked by SNPs rs3158129 and rs13475900. Based on the chromosomal position, the candidate cataract locus γ-crystallin gene cluster (Cryg) was investigated by sequencing. A single base deletion (299delG) in exon 3 of Cryga which led to a frame-shift of amino acid sequence from position 91 was identified. As a result of this mutation, the sequences of the 3rd and 4th Greek-key motifs of the γA-crystallin are replaced with an unrelated C-terminal peptide of 75 residues long. Coincidentally, the point mutation generated a HindIII restriction site, allowing the identification of the CrygaSecc mutant allele by RFLP. Western blot analysis of 3-week old lenses showed that the expression of γ-crystallins was reduced in the CrygaSecc mutant. Furthermore, in cell transfection assays using CrygaSecc mutant cDNA expression constructs in 293T, COS-7 and human lens epithelial B3 cell lines, the mutant γA-crystallins were enriched in the insoluble fractions and appeared as insoluble aggregates in the transfected cells. In conclusion, we have demonstrated that the Secc mutation leads to the generation of CrygaSecc proteins with reduced solubility and prone to form aggregates within lens cells. Accumulation of mutant proteins in the lens fibers would lead to cataract formation in the Secc mutant.
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Affiliation(s)
- Man Hei Cheng
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Chung Nga Tam
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Kwong Wai Choy
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Hung Tsang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sze Lan Tsang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - You Qiang Song
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Centre for Reproduction Development and Growth, Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| | - Mai Har Sham
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Centre for Reproduction Development and Growth, Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
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