Ubiquitin-mediated protein degradation is a complex process, and many of the signals remain unknown. One known signal involves recognition of amino acids in a processed protein that are either stabilizing (Ala, Gly, Met, Ser, etc.) or destabilizing (Arg, Asp, Leu, Lys, Phe, etc.), and are located at:
A) a helix-turn-helix motif in the protein.
B) a lysine-containing target sequence in the protein.
C) a zinc finger structure in the protein.
D) the amino-terminus of the protein.
E) the carboxy-terminus of the protein.
Protein amino acid side chains can hydrogen bond in the major groove of DNA, and discriminate between each of the four possible base pairs. In which one of the following groups of amino acids can all three members potentially be used in such DNA-protein recognition?
A) Ala, Asn, Glu
B) Arg, Gln, Leu
C) Asn, Gln, Trp
D) Asn, Glu, Lys
E) Glu, Lys, Pro