B = log2M (bits) | Number of bits for M symbols | [1] |
C = dspace log2(P∕N + 1) (bits/mmo) | Molecular machine capacity | [2, 3] |
D = 2dspace ≪ 3n- 6 | Dimensionality of a molecular machine coding space | [2] |
≤ D < | Lower and upper dimensionality bounds | [4] |
dspace = D∕2 | Number of ‘pins’ a molecular machine uses | [2, 3] |
ΔG (joules/mmo) | Free energy dissipated by a molecular machine in an operation | [2, 3] |
d.f. = 3n- 6 | Degrees of freedom for n atoms | [2] |
Emin = kBT ln2 (joules per bit) | A version of the Second Law of Thermodynamics that can be used as an ideal conversion factor between energy and bits | [5, 6] |
ϵt = = | Theoretical maximum molecular efficiency | [5, 6, 4] |
ϵr ≤ ϵt | Real (or measured) molecular efficiency | [5, 6] |
kB (joules/kelvin) | Boltzmann’s constant | |
λ = R∕2 | Compressed bases: the number of bases a binding site would take up if the information of the site was compressed as small as possible. | |
M = 2B | Number of symbols corresponding to B bits | |
mmo | Molecular machine operation | [2, 7] |
μ | Mean of Gaussian distribution | |
σ | Standard deviation of Gaussian distribution | |
π | Circle circumference/radius, something to eat | |
n | Number of atoms in a molecular machine. see d.f. | |
N (joules/mmo) | Thermal noise flowing through a molecular machine during an opertion | [2, 8, 9] |
P = -ΔG (joules/mmo) | Energy dissipated by a molecular machine in an opertion | [2, 3] |
p(x) = e- | Probabilty of x for a Gaussian distribution | |
quincunx | Galton’s Quincunx - a device that demonstrates the formation of a Gaussian distribution. See http://tinyurl.com/GaltonQuincunx | |
R (bits/mmo) | Information gained during a molecular machine operation, often of a binding site | [10] |
Renergy ≡-ΔG∘∕Emin (bits per mmo) | The maximum bits that can be gained for the given free energy dissipation | [5, 6] |
ρ = P∕N | Energy dissipation of a molecular machine normalized by the thermal noise flowing through the machine | |
T (K) | Absolute temperture, Kelvin | |
x | Voltage (for a communications system) or total potental and kinetic energy for a molecular machine | |
y | See x | |
[1] T. D. Schneider. Information theory primer, with an appendix on logarithms. Published on the web, 2013, 2013. https://doi.org/10.13140/2.1.2607.2000, https://alum.mit.edu/www/toms/papers/primer/.
[2] T. D. Schneider. Theory of molecular machines. I. Channel capacity of molecular machines. J. Theor. Biol., 148:83–123, 1991. https://doi.org/10.1016/S0022-5193(05)80466-7, https://alum.mit.edu/www/toms/papers/ccmm/.
[3] T. D. Schneider. Theory of molecular machines. II. Energy dissipation from molecular machines. J. Theor. Biol., 148:125–137, 1991. https://doi.org/10.1016/S0022-5193(05)80467-9, https://alum.mit.edu/www/toms/papers/edmm/.
[4] T. D. Schneider and V. Jejjala. Restriction enzymes use a 24 dimensional coding space to recognize 6 base long DNA sequences. PLoS One, 14:e0222419, 2019. https://doi.org/10.1371/journal.pone.0222419, https://alum.mit.edu/www/toms/papers/lattice/.
[5] T. D. Schneider. 70% efficiency of bistate molecular machines explained by information theory, high dimensional geometry and evolutionary convergence. Nucleic Acids Res., 38:5995–6006, 2010. https://doi.org/doi:10.1093/nar/gkq389, https://alum.mit.edu/www/toms/papers/emmgeo/.
[6] T. D. Schneider. A brief review of molecular information theory. Nano Communication Networks, 1:173–180, 2010. https://doi.org/10.1016/j.nancom.2010.09.002, https://alum.mit.edu/www/toms/papers/brmit/.
[7] T. D. Schneider. Sequence logos, machine/channel capacity, Maxwell’s demon, and molecular computers: a review of the theory of molecular machines. Nanotechnology, 5:1–18, 1994. https://doi.org/10.1088/0957-4484/5/1/001, https://alum.mit.edu/www/toms/papers/nano2/.
[8] J. B. Johnson. Thermal agitation of electricity in conductors. Physical Review, 32:97–109, 1928. https://doi.org/10.1103/PhysRev.32.97.
[9] H. Nyquist. Thermal agitation of electric charge in conductors. Physical Review, 32:110–113, 1928. https://doi.org/10.1103/PhysRev.32.110.
[10] T. D. Schneider, G. D. Stormo, L. Gold, and A. Ehrenfeucht. Information content of binding sites on nucleotide sequences. J. Mol. Biol., 188:415–431, 1986. https://doi.org/10.1016/0022-2836(86)90165-8, https://alum.mit.edu/www/toms/papers/schneider1986/.