title: Natively unfolded human prothymosin alpha adopts partially folded collapsed conformation at acidic pH.
abstract: Prothymosin alpha has previously been shown to be unfolded at neutral pH, thus belonging to a growing family of "natively unfolded" proteins. The structural properties and conformational stability of recombinant human prothymosin alpha were characterized at neutral and acidic pH by gel filtration, SAXS, circular dichroism, ANS fluorescence, (1)H NMR, and resistance to urea-induced unfolding. Interestingly, prothymosin alpha underwent a cooperative transition from the unfolded state into a partially folded conformation on lowering the pH. This conformation of prothymosin alpha is a compact denatured state, with structural properties different from those of the molten globule. The formation of alpha-helical structure by the glutamic acid-rich elements of the protein accompanied by the partial hydrophobic collapse is expected at lower pH due to the neutralization of the negatively charged residues. It is possible that such conformational changes may be associated with the protein function.
authors.affiliation: Institute for Biological Instrumentation, Russian Academy of Sciences, 142292 Pushchino, Moscow Region, Russia. uversky@hydrogen.ucsc.edu
authors.forename: V N
authors.initials: VN
authors.lastname: Uversky
authors.forename: J R
authors.initials: JR
authors.lastname: Gillespie
authors.forename: I S
authors.initials: IS
authors.lastname: Millett
authors.forename: A V
authors.initials: AV
authors.lastname: Khodyakova
authors.forename: A M
authors.initials: AM
authors.lastname: Vasiliev
authors.forename: T V
authors.initials: TV
authors.lastname: Chernovskaya
authors.forename: R N
authors.initials: RN
authors.lastname: Vasilenko
authors.forename: G D
authors.initials: GD
authors.lastname: Kozlovskaya
authors.forename: D A
authors.initials: DA
authors.lastname: Dolgikh
authors.forename: A L
authors.initials: AL
authors.lastname: Fink
authors.forename: S
authors.initials: S
authors.lastname: Doniach
authors.forename: V M
authors.initials: VM
authors.lastname: Abramov
mesh_terms: D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D011487:Protein Conformation; D017510:Protein Folding; D011498:Protein Precursors / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012996:Solutions; D013947:Thymosin / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D011498:Protein Precursors; D011994:Recombinant Proteins; D012996:Solutions; C040782:prothymosin alpha; D013947:Thymosin