Some amino acids questions

[mathbeauty]

1.) List the one letter code for the two amino acids that you would expect more frequently near the N-terminus of an alpha helix than its C-terminus.

2.) What do the amino acids K and M have in common?

3.) List the one letter code for the residue that cannot donate a hydrogen bond from its backbone.

4.) List the one letter code for the three β-branched amino acids.

5.) List the three letter and one letter code for the three amino acids that you would expect to form salt bridges with a DNA phosphate backbone.

6.) List the one letter code for all the amino acids that have side chains which cannot participate in hydrogen bonds.

7.) List the one-letter code for all the amino acids with aromatic side chains and note those that cannot accept a hydrogen bond with their side chain.

[jyaron]

These could easily be answered by searching google.. :?