Where are hydrophobic amino acids found in cell

The phospholipid molecules of the membrane bilayer actually protect these portions of transmembrane proteins from energetically unfavorable interactions with the aqueous environment. The hydrophobic, membrane-spanning segments of transР’Вmembrane proteins are specially adapted to the hydrophobic milieu in which they reside. Most membrane-spanning segments-that is, the short stretches of amino acids that pass through the membrane once-are composed mainly of these nonpolar amino acids, in concert with polar, uncharged amino acids. Not surprisingly, therefore, these hydrophobic side chains are quite comfortable in the hydrophobic environment of the bilayer core. These aromatic or uncharged aliphatic groups are almost as difficult to solvate in water as are the fatty-acid side chains of the membrane phospholipids themselves.

The side chains of the eight amino acids listed in the upper portion of Table 2-1 are hydrophobic. How can membrane-spanning proteins remain stably associated with the bilayer in a conformation that requires at least some portion of their amino-acid sequence to be in continuous contact with the membrane's hydrophobic central core? The answer to this question can be found in the special structures of those protein domains that actually span the membrane. Boron MD, PhD, in Medical Physiology, 2017 The membrane-spanning portions of transmembrane proteins are usually hydrophobic РћВ± helices

Where are hydrophobic amino acids found in cell