Novel compounds are provided that bind to polo-like kinases through the polo-box domain. In certain embodiments, the novel compounds are PEGylated peptides. The PEGylated peptides in accordance with the invention demonstrate high PBD-binding affinity. In certain embodiments, the PEGylated peptides have also achieved activities in whole cell systems. The invention also provides compounds that bind polo-like kinases through the polo-box domain and possess reduced anionic charge. Further provided are methods of design and/or synthesis of the PEGylated peptides and methods of use thereof. The invention provides methods of use of the compounds and methods of synthesis of the compounds.