- Associate Professor of Chemistry, Butler University (2015 - Present)
- Assistant Professor of Chemistry, Butler University (2009 - 2014)
- Postdoctoral Research Fellow (American Cancer Society Fellow and HHMI Research Associate), Harvard University (2007 - 2009). Research Advisor: Dr. Erin K. O'Shea
- PhD Biochemistry, University of Wisconsin-Madison (2007). Research Advisor: Dr. Ronald T. Raines.
My laboratory is globally interested in serine hydrolases: their structure, function, enzymatic activity, biological activity, and therapeutic potential. Specifically, we are interested in:
- developing novel fluorogenic and antibacterial substrate libraries. (See Lukowski et al, Ellis et al, and Hedge et al). We have an active collaboration with Dr. Luke Lavis at the HHMI Janelia Research Campus to design, construct, and test new fluorogenic and antibiotic based serine hydrolase substrates. Synthetic projects continue involving the expansion of a library of diverse fluorogenic hydrolase substrates and ester based derivatives of common antibiotics.
- characterizing global serine hydrolase activity in Mycobacterium. (See Lukowski et al.) We have been using our library of fluorogenic hydrolase activity to measure changes in global hydrolase activity across different growth conditions. The goal is to identify novel serine hydrolases whose activity is upregulated under mycobacterial specific growth conditions.
- determining the structural and functional properties of acyl protein thioesterases. (See Fillippova et al) We have focused on the dynamic structure and properties of a bacterial serine hydrolase from Francisella tularensis. This enzyme undergoes an unusual active to inactive structural transition that appears to dually control its enzymatic and membrane binding. The goal is to understand the structural factors controlling this transition and to correlate this with its biological function.
I have an active undergraduate research program with 6 - 10 undergraduate students per semester and 4 - 5 undergraduate students per summer research period. Summer research students obtain funding through the Butler Summer Institute (BSI), through internal funding from Butler, and through coverage from external grants from the NSF and NIH. I have mentored students with majors from chemistry to biology to pharmacy and starting from first year students to fourth year students. Students working in my laboratory have continued onto top graduate school programs in biochemistry, molecular biology, chemistry, genetics, and inorganic chemistry, onto top medical and dental schools, and into different chemical and business industry positions.
Research Publications: (*Indicates Undergraduate Author)
- Lukowski JK*, Savas CJ*, Gehring AM*, McKary MG*, Adkins CT, Lavis LD, Hoops GC, & Johnson RJ (2014) Distinct substrate selectivity of a metabolic hydrolase from Mycobacterium tuberculosis. Biochemistry.53, 7386-7395.
- Ellis EE*, Adkins CT, Galovska NM*,Lavis LD, & Johnson RJ. (2013) Decoupled roles for the atypical bifurcated binding pocket of the ybfF hydrolase. ChemBioChem. 14, 1134-1144.
- Fillippova EI, Weston LA*,Kuhn ML, Geissler B, Gehring AM*, Armoush N, Adkins CT, Minasov G, Dubroska I,Shuvalova L, Winsor JR, Lavis LD, Satchell KJF, Becker DP, Anderson WF, & Johnson RJ (2013). Large scale structural rearrangement of a serine hydrolase from Francisella tularensis facilitates catalysis. J. Biol. Chem. 288,10522-10535.
- Hedge MH*, Gehring AM*,Adkins CT, Weston LA*, Lavis LD, & Johnson RJ (2012) The structural basis for the narrow substrate specificity of anacetyl esterase from Thermotoga maritime. Biochim Biophys Acta. 1824, 1024-1030.
- Johnson RJ, Lavis LD, & Raines RT (2007).Intraspecies regulation of ribonucleolytic activity. Biochemistry. 46, 13131-13140.
- Johnson RJ, Chao T-Y, Lavis LD, & Raines RT (2007). Cytotoxic ribonucleases: The dichotomy of Coulombic forces.Biochemistry. 46, 10308-10316.
- Johnson RJ, Lin SR*, & Raines RT (2007). Genetic selection to reveal the role of a buried, conserved serine residue. Protein Science.16, 1609-1616.
- Johnson RJ, McCoy JG, Bingman CA, Phillips GN, & Raines RT (2007). Inhibition of human pancreatic ribonuclease by the human ribonuclease inhibitor protein. Journal of Molecular Biology. 368, 434-449.
- Johnson RJ, Lin SR*, & Raines RT (2006). A ribonuclease zymogen activated by the NS3 protease of thehepatitis C virus. FEBS Journal. 273,5457-5465.
- Reiter NJ, Nikstad LJ, Allmann AM, Johnson RJ, & Butcher SE (2003). Structure of the U6 RNA intramolecular stem-loop harboring an Sp-phosphorothioate modification. RNA. 9, 533-42.
- RJ Johnson. Investigation of mycobacterial hydrolases and their role in lipolysis. National Institutes of Health. NIH R15 Award. May 2015 - April 2018.
- RJ Johnson. Determining the connection between the structural rearrangement of a bacterial serine hydrolase and its biological function. Indiana Academy of Sciences Senior Research Grant. May 2015 - April 2016.
- RJ Johnson. Determining the substrate specificity of ester hydrolases from Mycobacterium tuberculosis. Indiana Academy of Sciences Senior Research Grant. May 2012 - April 2013.
- RJ Johnson (PI), J Kowalski (Co-PI), & G Hoops (Co-PI). An integrated series of student-driven, research-based undergraduate laboratory courses linking chemical biology, biochemistry, and neurobiology. National Science Foundation. Transforming Undergraduate Education in Science. May 2012 - April 2015.
- RJ Johnson. Determining the substrate specificity of bacterial esterases using latent fluorophores. Indiana Academy of Sciences Senior Research Grant. November 2010 - October 2011.
- Classroom undergraduate research laboratories and inquiry based research laboratories.
- Active classroom learning styles, especially incorporation of scientific skills, active discourse, and argumentation into the classroom.
- Incorporation of new classroom technologies, including molecular visualization laboratories.
- Assessment of student learning
- CH361: Biochemistry I (Amino acids, peptides, proteins, enzymes, and carbohydrates)
- CH462: Biochemistry II (Central dogma, signal transduction, and metabolism)
- CH463: Biochemistry Lab (Writing intensive, inquiry based laboratory)
- CH432: Synthesis and Characterization (Inquiry based laboratory)
- CH105: Introductory Chemistry I (Atomic structure, geometry, bonding, and solution reactivity)
- CH106: Introductory Chemistry II (Acid/Base, kinetics, equilibrium, thermodynamics, and electrochemistry)
- CH492: Chemistry Seminar (Scientific presentation)
- CH493/CH494: Undergraduate Research Mentoring
Teaching and Learning Publications: (*Indicates Undergraduate Author)
- Johnson RJ, Hoops GC, Savas CJ*, Kartje Z*, Lavis LD (2015) A sensitive and robust enzyme kinetic experiment using microplates andfluorogenic ester substrates. J. Chem Educ. 92, 385-388.
- Johnson RJ, Bartels A*, Erkilla R*, Green N*, Han S*,Holt N*, Jones M*, Lange D*, Maddalone K*, Morris J*, Mughmaw R*, O’Connor D*,Risselmann N*, Sharp C*, Stephens D*, Wright A*, Yothment E*, Zemtsov G* (2014) Proteopedia Entry: Mammalian Serine Hydrolases. Biochem. Mol. Biol. Educ.Published Online November 18th 2014. DOI: 10.1002/bmb.20840
- Johnson RJ, Hoops G, Savas CJ*, & Kartje Z* (2014) Rapid and adaptable measurement of protein thermal stability by differentialscanning fluorimetry: Updating a common biochemical laboratory experiment. J. Chem. Educ. 91, 1077-1080.
- Johnson RJ (2014) Teaching foundational topics and scientific skills in biochemistry within the conceptual framework of HIV protease. Biochem. Mol. Biol. Educ. 42, 299-304.
- Johnson RJ, Andorfer M*, Chaffee A*, Clark M*, Clarke N*, Douglass G*, Ellis E*, Fischer E*, Fuller C*, Garnett L*, Gehring A*, Heckman L*, Kroupa D*, Liu L*, Proimos D*, Raebel M*, Shaw K*, Slack M*, Trautmann D*, & Trefilek B* (2012) Proteopedia entry: Bovine pancreatic Ribonuclease A. B