Peptide backbone cyclization is an important bio-engineering tool that has been widely used to control the stability, structure and biological role of small peptides. Here we have analyzed the effect of ligand binding on the backbone dynamics of a linear and circular construct of N-terminal SH3 domain of the Murine C-Crk adapter protein. We have also determined the residues on the protein surface involved in binding with the ligand by carrying out a series of HSQC titration experiments at different (ligand/protein) concentrations. This is the first time that the interface for the adapter protein Murine c-Crk N-SH3 domain in complex with C3G derived peptide (ligand) in solution has been determined.