Within the enzyme family of phosphagen kinases, we find numerous enzymes that exhibit dimeric negative cooperativity in which the ligand binding in one subunit decreases the adjacent subunit’s affinity for ligand. During this study, we attempted to ascertain possible structural determinants of negative cooperativity in phosphagen kinases. By comparing two phosphagen kinases, Oryctolagus cuniculus creatine kinase, which exhibits negative cooperativity, and Neanthes diversicolor glycocyamine kinase which exhibits no cooperativity, we identified one amino acid, H7, which may be a potential structural determinant of negative cooperativity within the phosphagen kinase enzyme family. To test this hypothesis, a H7A mutant was synthesized and its cooperativity was examined via Isothermal Titration Calorimetry (ITC). Due to unusual binding activity in the H7A mutant, the cooperativity of H7A could not be definitively determined as the resulting binding data was not a good fit to any binding models. Although we were unable to determine the cooperativity of the H7A mutant, the data does suggest that the mutation affects the ability of the enzyme to bind MgADP. The exact mechanism in which the ability to bind MgADP is altered in the mutant is an area for further investigation.


Fraga, Dean


Biochemistry and Molecular Biology




phosphagen kinase, negative cooperativity, isothermal titration calorimetry

Publication Date


Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis



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