James M. Murphy is a researcher in protein signaling and the functions of pseudokinases, kinase-like protein domains with altered residues normally associated with catalysis. In a 2014 collaborative study, James M. Murphy and colleagues developed a thermal shift assay to classify 31 pseudokinase protein domains according to their binding of nucleotides and metal ions.[ref]
A robust methodology to subclassify pseudokinases based on their nucleotide-binding properties by James M. Murphy and others. Abstract and classification results; Biochemical Journal 457, 323–334, 2014
The key distinction is between binding and chemical activity. A protein may bind ATP without efficiently transferring its phosphate group. The thermal shift assay measures changes in thermal stability associated with binding, while an ordinary kinase activity assay can register activity from a small contaminating protein kinase. The study found four binding classes, including pseudokinases with no detectable binding and others whose binding depended on metal ions. This showed why the label pseudokinase cannot substitute for testing an individual protein.[ref]
A robust methodology to subclassify pseudokinases based on their nucleotide-binding properties by James M. Murphy and others. Abstract: four nucleotide/cation-binding classes and contamination caveat; Experimental: thermal-shift assays
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