Unfolding and refolding of cytochrome c driven by the interaction with lipid micelles \ud

Article English OPEN
Sanghera, Narinder ; Pinheiro, Teresa (2000)
  • Publisher: Canbridge University Press
  • Related identifiers: doi: 10.1110/ps.9.6.1194
  • Subject: QR
    mesheuropmc: enzymes and coenzymes (carbohydrates) | environment and public health

Binding of native cyt c to L-PG micelles leads to a partially unfolded conformation of cyt c. This micelle-bound state has no stable tertiary structure, but remains as -helical as native cyt c in solution. In contrast, binding of the acid-unfolded cyt c to L-PG micelles induces folding of the polypeptide, resulting in a similar helical state to that originated from the binding of native cyt c to L-PG micelles. Far-ultraviolet (UV) circular dichroism (CD) spectra showed that this common micelle-associated helical state (HL) has a native-like -helix content, but is highly expanded without a tightly packed hydrophobic core, as revealed by tryptophan fluorescence, near-UV, and Soret CD spectroscopy. The kinetics of the interaction of native and acid-unfolded cyt c was investigated by stopped-flow tryptophan fluorescence. Formation of HL from the native state requires the disruption of the tightly packed hydrophobic core in the native protein. This micelle-induced unfolding of cyt c occurs at a rate 0.1 s1, which is remarkably faster in the lipid environment compared with the expected rate of unfolding in solution. Refolding of acid-unfolded cyt c with L-PG micelles involves an early highly helical collapsed state formed during the burst phase (<3 ms), and the observed main kinetic event reports on the opening of this early compact intermediate prior to insertion into the lipid micelle.
  • References (44)
    44 references, page 1 of 5

    Babul J, Stellwagen E. 1972. Participation of the protein ligands in the folding of cytochrome c. Biochemistry 11:1195-1200.

    Bryson EA, Rankin SE, Carey M, Watts A, Pinheiro TJT. 1999. Folding of apocytochrome c in lipid micelles: Formation of a-helix precedes membrane insertion. Biochemistry 38:9758-9767.

    Bushnell GW, Louie GV, Brayer GD. 1990. High-resolution three-dimensional structure of horse cytochrome c. J Mol Biol 214:585-595.

    Bychkova VE, Ptitsyn OB. 1993. The molten globule in vitro and in vivo. Chemtracts Biochem Mol Biol 4:133-163.

    Chan C-K, Takahashi S, Rousseau DL, Eaton WA, Hofrichter J. 1997. Submillisecond protein folding kinetics studied by ultrarapid mixing. Proc Natl Acad Sci USA 94:1779-1784.

    Colón W, Elöve GA, Wakem LP, Sherman F, Roder H. 1996. Side chain packing of the N- and C-terminal helices plays a critical role in the kinetics of cytochrome c folding. Biochemistry 35:5538-5549.

    Colón W, Elöve GA, Wakem LP, Sherman F, Roder H. 1997. Identification of the predominant non-native histidine ligand in unfolded cytochrome c. Biochemistry 36:12535-12541.

    Cortese JD, Voglino AL, Hackenbrock CR. 1998. Multiple conformations of physiological membrane-bound cytochrome c. Biochemistry 37:6402- 6409.

    Davies AM, Guillemette JG, Smith M, Greenwood C, Thurgood AGP, Mauk AG, Moore GR. 1993. Redesign of the interior of mitochondrial cytochrome c by site-directed mutagenesis. Biochemistry 32:5431-5435.

    de Jongh HHJ, de Kruijff B. 1990. The conformational changes of apocytochrome c upon binding to phospholipid vesicles and micelles of phospholipid based detergents. A circular dichroism study. Biochim Biophys Acta 1029:105-112.

  • Similar Research Results (1)
  • Metrics
    0
    views in OpenAIRE
    0
    views in local repository
    84
    downloads in local repository

    The information is available from the following content providers:

    From Number Of Views Number Of Downloads
    Warwick Research Archives Portal Repository - IRUS-UK 0 84
Share - Bookmark