Abstract #1903

Synthesis of Human Protamine-1 (HPRM1), a Novel CEST Contrast Agent

Nikita Oskolkov¹, Kannie W.Y. Chan², Amnon Bar-Shir², Peter C.M. van Zijl¹,³, Jeff W.M. Bulte²,⁴, Assaf A. Gilad²,⁴, Michael T. McMahon¹,³

¹Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; ²Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; ³F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States; ⁴Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, MD, United States

We have synthesized human protamine-1 (hPRM1), a compound biologically relevant for packing cellular DNA, which is rich in arginine and generates high CEST contrast associated with the exchangeable protons in the guanidyl group. We have also determined how the contrast varies upon binding of hPRM1 to nucleotides, the natural role of this protein, which is relevant to how it might perform in vivo as contrast material. This synthetic approach has resulted in a high yield and retention of the peptides ability to bind DNA, potentially enabling use of hPRM-1 as an alternative to recombinant or naturally occurring protamine.