NMR structure of CmPI-II, a non- classical Kazal protease inhibitor: Understanding its conformational dynamics and subtilisin A inhibition.

•CmPI-II is a non-classical Kazal inhibitor with an unique spatial disposition of N-terminal region and CI-CV disulphide bond conformation.•N-terminal region and RSL of CmPI-II are highly flexible in solution.•CmPI-II N-terminal region, RSL and α-helix describe coupled motions.•P2 and P2′ sites of CmPI-II have the higher energetic contribution for binding subtilisin A.