title: Effect of position-specific single-point mutations and biophysical characterization of amyloidogenic peptide fragments identified from lattice corneal dystrophy patients.
abstract: Corneal stromal dystrophies are a group of genetic disorders that may be caused by mutations in the transforming growth factor β-induced (TGFBI) gene which results in the aggregation and deposition of mutant proteins in various layers of the cornea. The type of amino acid substitution dictates the age of onset, anatomical location of the deposits, morphological features of deposits (amyloid, amorphous powder or a mixture of both forms) and the severity of disease presentation. It has been suggested that abnormal turnover and aberrant proteolytic processing of the mutant proteins result in the accumulation of insoluble protein deposits. Using mass spectrometry, we identified increased abundance of a 32 amino acid-long peptide in the 4th fasciclin-like domain-1 (FAS-1) domain of transforming growth factor β-induced protein (amino acid 611-642) in the amyloid deposits of the patients with lattice corneal dystrophies (LCD).In vitrostudies demonstrated that the peptide readily formed amyloid fibrils under physiological conditions. Clinically relevant substitution (M619K, N622K, N622H, G623R and H626R) of the truncated peptide resulted in profound changes in the kinetics of amyloid formation, thermal stability of the amyloid fibrils and cytotoxicity of fibrillar aggregates, depending on the position and the type of the amino acid substitution. The results suggest that reduction in the overall net charge, nature and position of cationic residue substitution determines the amyloid aggregation propensity and thermal stability of amyloid fibrils.
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.|School of Biological Sciences, Nanyang Technological University, Singapore 637551.
authors.forename: Venkatraman
authors.initials: V
authors.lastname: Anandalakshmi
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.|Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Elavazhagan
authors.initials: E
authors.lastname: Murugan
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.
authors.forename: Eunice Goh Tze
authors.initials: EGT
authors.lastname: Leng
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.
authors.forename: Lim Wei
authors.initials: LW
authors.lastname: Ting
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.|Department of Veterinary Medicine, Surgery University of Missouri, Columbia, MO, U.S.A.
authors.forename: Shyam S
authors.initials: SS
authors.lastname: Chaurasia
authors.affiliation: RIKEN Centre for Life Science Technologies, Kanagawa 230-0045, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamazaki
authors.affiliation: RIKEN Centre for Life Science Technologies, Kanagawa 230-0045, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Nagashima
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.
authors.forename: Benjamin Lawrence
authors.initials: BL
authors.lastname: George
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore.|Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Gary Swee Lim
authors.initials: GSL
authors.lastname: Peh
authors.affiliation: School of Biological Sciences, Nanyang Technological University, Singapore 637551 jodmehta@gmail.com lakshminus@gmail.com kpervushin@ntu.edu.sg.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Pervushin
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore jodmehta@gmail.com lakshminus@gmail.com kpervushin@ntu.edu.sg.|Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Rajamani
authors.initials: R
authors.lastname: Lakshminarayanan
authors.affiliation: Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Singapore jodmehta@gmail.com lakshminus@gmail.com kpervushin@ntu.edu.sg.|Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School.|Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751.
authors.forename: Jodhbir S
authors.initials: JS
authors.lastname: Mehta
mesh_terms: D019943:Amino Acid Substitution; D000682:Amyloid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D058227:Amyloidogenic Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003315:Cornea / Q000166:cytology / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D003317:Corneal Dystrophies, Hereditary / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D066263:Protein Aggregation, Pathological / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055550:Protein Stability; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D016212:Transforming Growth Factor beta / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D000682:Amyloid; D058227:Amyloidogenic Proteins; D005136:Eye Proteins; D010446:Peptide Fragments; C508960:TGFB1 protein, human; C000620822:TGFBI protein (611-642), human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1
keywords: TGFBIp; amino acid substitution; amyloid; corneal dystrophy; protein aggregation; β-sheet propensity