Conformational polymorphism, stability and aggregation in spider dragline silks proteins.
Spider silk is spun in a complex and unique process, thought to depend on a hydrophobic conversion of a predominantly disordered to a beta-sheet rich protein structures. To test this hypothesis we monitored the effect of cationic (DOTAC) and anionic (alkyl sulfate) detergents and of (ii) solvent polarity using a series of alcohols on the secondary structure transition in dilute solutions of native spidroin. Our results showed that the detergents hydrophilic head charge and hydrophobic tail length cooperatively induced either a transition to the beta-sheet rich form or a stable helical state. Changing the solvent polarity showed that HFIP and TFE induced formation of stable helical forms whereas MeOH, EtOH and IsoP induced a kinetically driven formation of beta-sheet rich structure.
Dicko
Cedric
C
Department of Zoology, Oxford University, Oxford OX1 3PS, UK. cedric.dicko@zoo.ox.ac.uk
Knight
David
D
Kenney
John M
JM
Vollrath
Fritz
F
D019840:2-Propanol / Q000737:chemistry; D000438:Alcohols / Q000737:chemistry; D000818:Animals; D000838:Anions; D001665:Binding Sites; D002412:Cations; D002942:Circular Dichroism; D003902:Detergents / Q000737:chemistry / Q000494:pharmacology; D000431:Ethanol / Q000737:chemistry; D005349:Fibroins / Q000737:chemistry; D019476:Insect Proteins / Q000737:chemistry; D007700:Kinetics; D000432:Methanol / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D047011:Silk / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013112:Spiders; D013431:Sulfates / Q000494:pharmacology; D013816:Thermodynamics; D013997:Time Factors
D000438:Alcohols; D000838:Anions; D002412:Cations; D003902:Detergents; D019476:Insect Proteins; D000644:Quaternary Ammonium Compounds; D047011:Silk; D012997:Solvents; D013431:Sulfates; D000431:Ethanol; D005349:Fibroins; C022806:dodecyltrimethylammonium; D019840:2-Propanol; D000432:Methanol