Circular dichroism studies of the mitochondrial channel, VDAC, from Neurospora crassa

Ling Shao, Kathleen W. Kinnally, Carmen A. Mannella

Research output: Contribution to journalArticle

Abstract

The protein that forms the voltage-gated channel VDAC (or mitochondrial porin) has been purified from Neurospora crassa. At room temperature and pH 7, the circular dichroism (CD) spectrum of VDAC suspended in octyl β- glucoside is similar to those of bacterial porins, consistent with a high β- sheet content. When VDAC is reconstituted into phospholipid liposomes at pH 7, a similar CD spectrum is obtained and the liposomes are rendered permeable to sucrose. Heating VDAC in octyl β-glucoside or in liposomes results in thermal denaturation. The CD spectrum irreversibly changes to one consistent with total loss of β-sheet content, and VDAC-containing liposomes irreversibly lose sucrose permeability. When VDAC is suspended at room temperature in octyl β-glucoside at pR <5 or in sodium dodecyl sulfate at pH 7, its CD spectrum is consistent with partial loss of β-sheet content. The sucrose permeability of VDAC-containing liposomes is decreased at low pH and restored at pH 7. Similarly, the pH-dependent changes in the CD spectrum of VDAC suspended in octyl β-glucoside also are reversible. These results suggest that VDAC undergoes a reversible conformational change at low pH involving reduced β-sheet content and loss of pore-forming activity.

Original languageEnglish (US)
Pages (from-to)778-786
Number of pages9
JournalBiophysical Journal
Volume71
Issue number2
StatePublished - Aug 1996

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Neurospora crassa
Circular Dichroism
Liposomes
Sucrose
Porins
Permeability
Temperature
Sodium Dodecyl Sulfate
Heating
Phospholipids
Hot Temperature
octyl-beta-D-glucoside

ASJC Scopus subject areas

  • Biophysics

Cite this

Shao, L., Kinnally, K. W., & Mannella, C. A. (1996). Circular dichroism studies of the mitochondrial channel, VDAC, from Neurospora crassa. Biophysical Journal, 71(2), 778-786.

Circular dichroism studies of the mitochondrial channel, VDAC, from Neurospora crassa. / Shao, Ling; Kinnally, Kathleen W.; Mannella, Carmen A.

In: Biophysical Journal, Vol. 71, No. 2, 08.1996, p. 778-786.

Research output: Contribution to journalArticle

Shao, L, Kinnally, KW & Mannella, CA 1996, 'Circular dichroism studies of the mitochondrial channel, VDAC, from Neurospora crassa', Biophysical Journal, vol. 71, no. 2, pp. 778-786.
Shao, Ling ; Kinnally, Kathleen W. ; Mannella, Carmen A. / Circular dichroism studies of the mitochondrial channel, VDAC, from Neurospora crassa. In: Biophysical Journal. 1996 ; Vol. 71, No. 2. pp. 778-786.
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