Author/Editor		Anderluh, Gregor; Goekce, Isa; Lakey, Jeremy H
Title		A natively unfolded toxin domain uses its receptor as a folding template
Type		članek
Source		J Biol Chem
Vol. and No.		Letnik 279, št. 21
Publication year		2004
Volume		str. 22002-9
Language		eng
Abstract		Natively unfolded proteins range from molten globules to disordered coils. They are abundant in eukaryotic genomes and commonly involved in molecular interactions. The essential N-terminal translocation domains of colicin toxins from Escherichia coli are disordered bacterial proteins that bind at least one protein of the Tol or Ton family. The colicin N translocation domain (CoIN-(1-90)), whieh binds to the C-terminal domain of ToIA (ToIA-(296421)), shows a disordered far-UV CD spectrum, no near-UV CD signal, and non-cooperative thermal unfolding. As expected, ToIA-(296-421) displays both secondary structure in far-LTV CD and tertiary structure in near-UV CD. Furthermore it shows a cooperative unfolding transition at 65 °C. CD spectra of the 1:1 eomplex show both increased secondary structure and colicin N-specific near-L1V CD signals. A new cooperative thermal transition at 35 °C is followed by the unchanged unfolding behavior of ToIA-(296-421). Fluorescence and surface plasmon resonance confirm that the new unfolding transition accompanies dissociation of CoIN-(1-90). Hence upon binding the disordered structure of CoIN-(1-90) converts to a cooperatively folded domain without altering the TolA-(296-421) structure.
Descriptors		ESCHERICHIA COLI COLICINS PROTEIN STRUCTURE, SECONDARY PROTEIN STRUCTURE, TERTIARY PROTEIN BINDING PROTEIN FOLDING SPECTROPHOTOMETRY, ULTRAVIOLET SPECTROMETRY, FLUORESCENCE CHROMATOGRAPHY, GEL