DNA Structure: Alphabet Soup for the Cellular Soul

Abstract

The story of DNA structure is as varied as it is interesting, the most famous tale being the “discovery” of B-DNA by Watson and Crick. For many biologists, this simple, but elegant structure is all that is needed for a basic, albeit superficial understanding of cellular genetics. A deeper appreciation for how DNA functions comes from the recognition that this is a highly malleable molecule, providing the cell with a plethora of conformations to exploit in replication and transcription. Some of these conformations can give rise to mistakes, while others help to repair those mistakes in the genetic code. In this chapter, we dive into the cellular pot and find a literal alphabet soup of DNA structures. We start our journey by presenting the fundamental principles that serve as the vocabulary to analyze and describe the features of nucleic acid structures. We will explore the conformational variations that lead from double-helices to complexes composed of three or four strands, then consider how conformations interconvert through various intermediates. Although B-DNA is the standard form in the cell, we suggest that this dance away from the norm is essential for cellular function, giving the cell life and, hence, its genetic soul.