This is aspartate is it might be in solution. The carboxyl group has lost a hydrogen. Also if you note the two oxygens coming from the bottom of the molecule, one was originally a hydroxyl group and has now lost its hydrogen to the solution. Thus the functional group is a negatively charged ion . This will be very hydrophilic .
Some amino acids have functional groups containing sulfur.
These are important structural amino acids because two sulfurs from distant amino acids in a polypeptide can link together to form strong covalent bonds that help to stabilize the structure of the polypeptide. This is cysteine. The yellow globe at the bottom represents a sulfur atom.