James C. Wang is a biochemist who trained as a chemical engineer before turning to biophysical chemistry and molecular biology. Wang discovered deoxyribonucleic acid (DNA) topoisomerases (or local enzymes) and proposed a mechanism for their operation in the 1970s. He also studied the configuration (or topology) of DNA, an approach that proved fruitful in helping to explain how the structure of the double helix coils and relaxes.

Wang once noted that his interest in DNA topology came about by chance. His training in engineering and chemistry had led him to study the physical basis of chemical processes. He began to think about the questions raised by the double helix structure of DNA soon after its discovery by molecular biologists James Watson and Francis Crick. His own study of DNA confirmed the unique structure. But it was not clear how the two tightly intertwined strands could unravel at the...