Europhys. Lett.
Volume 73, Number 3, February 2006
Page(s) 457 - 463
Section Interdisciplinary physics and related areas of science and technology
Published online 11 January 2006
Europhys. Lett., 73 (3), pp. 457-463 (2006)
DOI: 10.1209/epl/i2005-10418-2

Self-organised criticality and $\mth{1/f}$ noise in single-channel current of voltage-dependent anion channel

J. Banerjee1, M. K. Verma2, S. Manna1 and S. Ghosh3, 1

1  Department of Biophysics, University of Delhi South Campus Benito Juarez Road, New Delhi 110021, India
2  Department of Physics, Indian Institute of Technology - Kanpur 208016, India
3  Department of Animal Sciences, School of Life Sciences University of Hyderabad - Hyderabad 500046, India

received 11 June 2005; accepted in final form 12 December 2005
published online 11 January 2006

Noise profile of Voltage Dependent Anion Channel (VDAC) is investigated in open channel state. Single-channel currents through VDAC from mitochondria of rat brain reconstituted into a planar lipid bilayer are recorded under different voltage clamped conditions across the membrane. Power spectrum analysis of current indicates power law noise of 1/f nature. Moreover, this 1/f nature of the open channel noise is seen throughout the range of applied membrane potential from -30 to +30$\un{mV}$. It is being proposed that 1/f noise in open ion channel arises out of obstruction in the passage of ions across the membrane. The process is recognised as a phenomenon of self-organized criticality (SOC) like sandpile avalanche and other physical systems. Based on SOC it has been theoretically established that the system of ion channel follows power law noise as observed in our experiments. We also show that the first-time return probability of current fluctuations obeys a power law distribution.

87.15.-v - Biomolecules: structure and physical properties.
87.15.Aa - Theory and modeling; computer simulation.
87.15.Ya - Fluctuations.

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