EMAIL THIS PAGE TO A FRIEND

Proceedings of the National Academy of Sciences of the United States of America

Temperature dependence of amino acid hydrophobicities.


PMID 26034278

Abstract

The hydrophobicities of the 20 common amino acids are reflected in their tendencies to appear in interior positions in globular proteins and in deeply buried positions of membrane proteins. To determine whether these relationships might also have been valid in the warm surroundings where life may have originated, we examined the effect of temperature on the hydrophobicities of the amino acids as measured by the equilibrium constants for transfer of their side-chains from neutral solution to cyclohexane (K(w > c)). The hydrophobicities of most amino acids were found to increase with increasing temperature. Because that effect is more pronounced for the more polar amino acids, the numerical range of K(w > c) values decreases with increasing temperature. There are also modest changes in the ordering of the more polar amino acids. However, those changes are such that they would have tended to minimize the otherwise disruptive effects of a changing thermal environment on the evolution of protein structure. Earlier, the genetic code was found to be organized in such a way that--with a single exception (threonine)--the side-chain dichotomy polar/nonpolar matches the nucleic acid base dichotomy purine/pyrimidine at the second position of each coding triplet at 25 °C. That dichotomy is preserved at 100 °C. The accessible surface areas of amino acid side-chains in folded proteins are moderately correlated with hydrophobicity, but when free energies of vapor-to-cyclohexane transfer (corresponding to size) are taken into consideration, a closer relationship becomes apparent.

Related Materials

Product #

Image

Description

Molecular Formula

Add to Cart

539821
2-Methylpropane, 99.995%
C4H10
295450
2-Methylpropane, 99%
C4H10
494402
Butane, 99%
C4H10
443670
Butane, fuel for Micro Torch, contains no CFC gases
C4H10
GF93740384
Carbon - Vitreous, rod, 100mm, diameter 10mm, glassy carbon
C
GF65427587
Carbon - Vitreous, rod, 100mm, diameter 3.0mm, glassy carbon
C
GF05962765
Carbon - Vitreous, rod, 100mm, diameter 5.0mm, glassy carbon
C
GF68195403
Carbon - Vitreous, rod, 100mm, diameter 7.0mm, glassy carbon
C
GF23723423
Carbon - Vitreous, rod, 200mm, diameter 1.0mm, glassy carbon
C
GF91785134
Carbon - Vitreous, rod, 200mm, diameter 10mm, glassy carbon
C
GF78447707
Carbon - Vitreous, rod, 200mm, diameter 3.0mm, glassy carbon
C
GF45345562
Carbon - Vitreous, rod, 200mm, diameter 5.0mm, glassy carbon
C
GF24425805
Carbon - Vitreous, rod, 200mm, diameter 7.0mm, glassy carbon
C
GF93251011
Carbon - Vitreous, rod, 50mm, diameter 1.0mm, glassy carbon
C
GF20176680
Carbon - Vitreous, rod, 5mm, diameter 3.0mm, glassy carbon
C
GF59400233
Carbon - Vitreous, tube, 100mm, outside diameter 10mm, inside diameter 3mm, wall thickness 3.5mm, glassy carbon
C
GF39088648
Carbon - Vitreous, tube, 50mm, outside diameter 10mm, inside diameter 3mm, wall thickness 3.5mm, glassy carbon
C
GF07378476
Carbon - Vitreous, foam, 150x150mm, thickness 2.5mm, bulk density 0.05g/cm3, porosity 96.5%
C
GF39873369
Carbon - Vitreous, foam, 150x150mm, thickness 3.2mm, bulk density 0.05g/cm3, porosity 96.5%
C
GF61342220
Carbon - Vitreous, foam, 150x150mm, 0.05g.cmué, porosity 96.5%, 24 pores/cm
C
GF58042324
Carbon - Vitreous, foam, 275x330mm, thickness 3.2mm, bulk density 0.05g/cm3, porosity 96.5%
C
GF12408713
Carbon - Vitreous, foam, 275x330mm, 0.05g.cmué, porosity 96.5%, 24 pores/cm
C
GF04031132
Carbon - Vitreous, foam, 300x300mm, thickness 20mm, bulk density 0.05g/cm3, porosity 96.5%
C
GF06230922
Carbon - Vitreous, foam, 300x300mm, thickness 30mm, bulk density 0.05g/cm3, porosity 96.5%
C
GF95357526
Carbon - Vitreous, foil, 100x100mm, thickness 1.0mm, glassy carbon
C
GF61808889
Carbon - Vitreous, foil, 100x100mm, thickness 2.0mm, glassy carbon
C
GF09325009
Carbon - Vitreous, foil, 100x100mm, thickness 6.0mm, glassy carbon
C
GF22691426
Carbon - Vitreous, foil, 10x10mm, thickness 1.0mm, glassy carbon
C
GF74135628
Carbon - Vitreous, foil, 10x10mm, thickness 2.0mm, glassy carbon
C
GF99431523
Carbon - Vitreous, foil, 10x10mm, thickness 4.0mm, glassy carbon
C