title: Further investigation on potassium-induced conformation transition of Nephila spidroin film with two-dimensional infrared correlation spectroscopy.
abstract: We used two-dimensional (2D) correlation infrared spectroscopy to study further the potassium-induced conformation transition in Nephila spidroin films. It provided increased resolution and important new information on the sequence of events in the conformation transition process, showing that beta-sheet formed from the helical component before they formed from random coil. It also showed more evidence that formation of the 1691 cm(-1) (turn/bend) peak did not proceed with the same kinetics as the 1620 cm(-1) (antiparallel beta-sheet component) one, so we attribute the 1691 cm(-1) peak to turns which formed with different kinetics as the antiparallel beta-sheets. We present a single coherent and detailed hypothesis for the assembly and secondary structural transition of silk proteins in vivo and in vitro based on our findings and on evidence from other laboratories.
authors.affiliation: Department of Macromolecular Science, The Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, People's Republic of China.
authors.forename: Xianneng
authors.initials: X
authors.lastname: Peng
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Shao
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: David P
authors.initials: DP
authors.lastname: Knight
authors.forename: Peiyi
authors.initials: P
authors.lastname: Wu
authors.forename: Fritz
authors.initials: F
authors.lastname: Vollrath
mesh_terms: D000818:Animals; D005349:Fibroins / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D011487:Protein Conformation; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013112:Spiders / Q000737:chemistry; D013499:Surface Properties
chemical_list: D005349:Fibroins; D011188:Potassium