Proteins are synthesized as polypeptide chains

1
Mirror image protein engineering Rational design
of the unfolded state by targeting glycine
residues with positive f angles
Daniel P Raleigh State University of New York at
Stony Brook, Stony Brook NY 11794-3400
Protein stability can be increased by decreasing
the entropy of the unfolded state. Unfolded state
entropy can be decreased by the substitution of a
glycine with any other aminoacid since glycine
lacks a side chain and thus is the most flexible
residue in terms of the number of allowed
backbone conformations. Numerous attempts to make
use of this strategy have failed because glycine
often adopts a conformation which is not
compatible with an L-aminoacid, for example at
the C-termini of helices or in certain turns. The
use of D-aminoacids overcomes this problem
Glycine residues with positive f angles are often
found at the C-termini of helices. Replace of
these residues by D-aminoacids increases proteins
stability