Figure 1

Sample compatible solutes. a) Glycine betaine (usually abbreviated as betaine), b) glycerol, c) proline d) hydroxyetoine (also designated THP A) and e) ectoine (also designated THP B). The THPs (for tetrahydropyrimidine) have a structural similarity to the pyrimidine bases, see f) thymine as example. Note that the aromatic thymine ring is planar whereas the cyclic THPs are in half-chair conormation.