title: Modulation of Self-Assembly Process of Fibroin: An Insight for Regulating the Conformation of Silk Biomaterials.
abstract: Controlling the mechanism of self-assembly in proteins has emerged as a potent tool for various biomedical applications. Silk fibroin self-assembly consists of gradual conformational transition from random coil to β-sheet structure. In this work we elucidated the intermediate secondary conformation in the presence of Ca(2+) ions during fibroin self-assembly. The interaction of fibroin and calcium ions resulted in a predominantly α-helical intermediate conformation, which was maintained to certain extent even in the final conformation as illustrated by circular dichroism and attenuated total reflectance-Fourier transform infrared spectroscopy. Further, to elucidate the mechanism behind this interaction molecular modeling of the N-terminal region of fibroin with Ca(2+) ions was performed. Negatively charged glutamate and aspartate amino acids play a key role in the electrostatic interaction with positively charged calcium ions. Therefore, insights about modulation of self-assembly mechanism of fibroin could potentially be utilized to develop silk-based biomaterials consisting of the desired secondary conformation.
authors.affiliation: Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Dubey
authors.affiliation: Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India.
authors.forename: Sumit
authors.initials: S
authors.lastname: Murab
authors.affiliation: Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India.
authors.forename: Sandip
authors.initials: S
authors.lastname: Karmakar
authors.affiliation: Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India.
authors.forename: Pramit K
authors.initials: PK
authors.lastname: Chowdhury
authors.affiliation: Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India.
authors.forename: Sourabh
authors.initials: S
authors.lastname: Ghosh
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry*; D012831:Bombyx / Q000737:chemistry* / Q000502:physiology; D002118:Calcium / Q000737:chemistry*; D002413:Cations, Divalent; D002942:Circular Dichroism; D005349:Fibroins / Q000737:chemistry* / Q000302:isolation & purification; D018698:Glutamic Acid / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity
chemical_list: D002413:Cations, Divalent; D001224:Aspartic Acid; D018698:Glutamic Acid; D005349:Fibroins; D002118:Calcium