The HLH motif is often preceded by a stretch of highly ______ amino acids whose ______ charged side chains contact DNA and determine the transcription factor's sequence specificity.
A)basic,positively
B)basic,negatively
C)acidic,negatively
D)acidic,positively
E)hydrophobic,neutral

Question

Quizplus · Accepted Answer

The HLH motif is a basic motif, meaning it has positively charged amino acids. The charged side chains of these amino acids contact DNA to determine sequence specificity. Therefore, the correct answer is A, with "basic" being the highly charged amino acids and "positively" describing the charge of the side chains.

The HLH Motif Is Often Preceded by a Stretch of Highly