Scientific research often takes place at an interface, between people and between fields of study. Assoc. Prof. David Usher, chemistry and chemical biology, seems to live at such an interface, boasting a diverse range of interests in both his scientific research and his hobbies.

Usher studies the origins of life, a controversial topic in science. He currently teaches the large lecture course CHEM 2080: General Chemistry.

Usher received a chemistry set from his aunt at the age of 5, inspiring him to become a chemist. “In those days, chemistry sets actually had some interesting stuff in them, instead of just benign chemicals,” he said. Usher recalled that using test tubes and chemicals first sparked his interest in chemistry. “I understand that I said, ‘I want to be a chemist when I grow up.’”

Usher moved to New Zealand as an 11 year old, travelling 6 weeks from England by boat before arriving. There, Usher set up a lab in his home, and bought chemicals to experiment with. “There were the explosions that one is glad to have survived. It was fun,” Usher reminisced.

As an undergraduate at the Victoria University in Wellington, New Zealand, Usher continued to study chemistry, although he performed better in physics and even scored his lowest grade on an inorganic chemistry exam.

After staying at Wellington to earn a M.Sc. degree, Usher moved to University of Cambridge, England, where he studied organophosphates. These molecules contain carbon atoms, common to all organic compounds found in living organisms, bound to high energy inorganic phosphate groups, which are compounds made up of phosphorus and oxygen atoms. DNA and RNA — carriers of genetic information in living organisms — are built out of organophosphate molecules, making these molecules extremely significant in our understanding of the origins and replication of life.

Usher conducted postdoctoral research at Harvard University, and joined Cornell in 1965. His early research at Cornell involved RNase, an enzyme that catalyzes the breakdown of large chains of RNA into its individual components, which are called nucleotides.

Usher realized that his diverse interests could develop into chemical research that spanned multiple disciplines and broke into a new and more controversial field: the study of the origins of life. This field studies the transformation of inorganic, or noncarbon-based, molecules into complex macromolecules capable of replication, such as DNA, RNA and the proteins that make up living organisms.

“Some people thought that I was wasting an entire career by going into the field of origins,” Usher explained, adding that the topic has only recently gained professional respect. Usher discussed his fascination with Frank Drake, astronomy, the founder of the Search for Extra-Terrestrial Intelligence (SETI) projects, asking, “If one could provide an acceptable mechanism for the origin of life on this planet, would it increase the interest in people doing SETI?” The answer, he added, was a definite yes.

Influenced by Drake, Carl Sagan and other scientists involved with studying the origin of life, Usher changed the course of his research in the 1970’s to study the origins of life. “I thought it was an exciting place to combine my interests in astronomy, chemistry and biology,” he said. Although his subsequent research has not contributed much information for SETI, his research on RNA has contributed to the greater pool of knowledge on the possible origins of life.

Usher’s current research focuses on the ribosome, a large molecule within the cell that facilitates the assembly of proteins from individual amino acids. Proteins are used ubiquitously in living organisms to catalyze important reactions, provide structural support and act as chemical messengers in cells.

“The little niche we carved out [in the field of origins of life] is trying to understand how something as complicated as the ribosome could have arisen,” said Usher. “Protein synthesis [the function of a ribosome] is complicated; you have the [different types of] RNAs and proteins,” explained Usher. “It’s much too complicated to have suddenly arisen unless you believe in divine intervention. I am interested in simple versions of ribosomes.”

Usher studies how these simplified ribosomes can facilitate the formation of peptide bonds — bonds between amino acids — in order to create the first simple proteins. This research may eventually reveal how biological macromolecules were created from small, simple molecules.

Usher hopes that his research on the origins of peptide bond formation, which is funded by NASA, will eventually allow him to study the creation of specific sequences of amino acids, such as alternating amino acids with molecules that are alternately attracted to and repelled by water.

Usher owns a patent on amide-linked nucleotides, which are components of DNA or RNA that are linked together with three atoms including nitrogen, rather than the four-atom carbon-oxygen-phosphorus-oxygen linkage chain that occurs in natural DNA. Usher’s linkage can be used to increase the efficiency of a microarray — a tool that matches all of the unknown RNA in a cell with a set of known DNA in order to identify the genes expressed within the cell.

Usher’s work is unique not only because of the area it pertains to but also because of the way it is conducted. “For the past 8 years, we’ve been working entirely with undergraduate students,” Usher said. They’re bright and very enthusiastic, but the main problem is that they don’t have a lot of time.”

His involvement with undergraduates extends beyond his own research. This semester, Usher is teaching General Chemistry, where he is known for singing opera to his students. Usher also plays piano and competitive tennis in his spare time.

“Teaching is also a little bit like performing.” Usher said, after describing his musical interests. “I really have liked it. The teaching has been something that keeps one going because I appreciate the students."