13. Which one is incorrect?
(A)DNA footprinting reveals the sites where RNA binds on a DNA molecule.
(B)To determine the three-dimensional structure of a protein at atomic resolution, large proteins have to be crystallized and studied by x-ray diffraction.
(C)The structure of small proteins in solution can be determined by nuclear magnetic resonance analysis.
(D)Because proteins with similar structures often have similar functions, the biochemical activity of a protein can sometimes be predicted by searching for known proteins that are similar in their amino acid sequences.