It all started with an expression problem. Michael Gottesman and his lab members at the US National Cancer Institute in Bethesda, Maryland were studying a membrane protein involved in drug metabolism called P-glycoprotein to understand why some people develop resistance to chemotherapy during cancer treatment. But when the scientists tried to express large quantities of the protein in bacterial cells, they hit a wall.
“It was a real mess,” Gottesman recalls. “We couldn’t do it.”
The genetic code is read in triplets called codons, 64 of them representing just 20 amino acids. That means there is more than one codon for each amino acid, and different organisms preferentially use certain codons to make translation faster.