Genetics in Action: Mutation of Chromoproteins in First‐Semester Introductory Biology

In contrast to fluorescent proteins, chromoproteins provide a quick, reliable way to assess phenotype in visible light. In this course‐based undergraduate research experience (CURE), students utilized two different strategies to mutate the chromoproteins aeBlue and tsPurple: either intentionally or randomly. After a journal club highlighting diversity in chromoproteins, the conservation of their chromophores, and the targeted mutation of amilCP, students designed their own primers for site‐directed mutagenesis of either the aeBlue chromophore itself or amino acids near the chromophore. As a complementary technique, students used isothermal, error‐prone PCR with manganese chloride to induce mutations in the tsPurple plasmid. Potentially mutated DNAs were transformed into bacteria, and candidates for mutation were selected based on a loss of color relative to bacteria expressing the parent vector. Students analyzed mutants by DNA sequencing and protein expression (via SDS‐PAGE) to verify how changes to protein sequence contributed to protein function. Based on the phenotypes from the random mutagenesis, students also identified novel mutations in the chromoprotein that prevented color development. Understanding of the project was assessed through laboratory notebooks, formal laboratory papers, and presentations. Overall, this project provided an engaging, straightforward, and affordable way to visualize the relationship between protein structure and function while teaching first‐year college students basic molecular biology techniques. Support or Funding Information Soka University of America