Covalent Labeling of Human Neuroglobin with a 19F-Probe to Study its Conformational Changes Using 19F NMR

It is of interest to develop new approaches to probing protein conformational changes and protein–protein interactions. In this study, we covalently labeled human neuroglobin (Ngb) with a 19F-probe containing a Ph-OCF3 group at Cys120 and by introducing cysteine residues at specific positions in the C120S Ngb mutant. 19F NMR provides valuable insights into its conformational changes upon cleavage of the intramolecular disulfide bond of Cys46-Cys55, as well as its interactions with protein partners such as cytochrome c (Cyt c) through the formation of the Ngb-Cyt c complex. This study presents a convenient approach to investigating the dynamic properties of heme globins regulated by disulfide bonds and protein–protein interactions.