Chemical Syntheses and Biological Evaluation of CXCL14 and Its Site-Selectively Modified Methionine Sulfoxide-Containing Derivatives.

The access to methionine sulfoxide [Met(O)]-containing proteins is particularly valuable for studying this important type of post-translational modification (PTM). However, the lack of selective in vitro oxidation methods makes it difficult to obtain homogeneous proteins with accurate and controllable incorporation of Met(O), particularly the ones with multiple methionines. Here, we report a chemical approach to synthesize methionine-oxidized human chemokine CXCL14 in a site-selective manner. The in vitro chemotaxis activities of synthetic proteins have also been evaluated.