The central interactive region of human MxA GTPase, recognized by mAb 2C12, is critical for the regulation of GTPase activity and viral target recognition.
The central interactive region of human MxA GTPase, recognized by mAb 2C12, is critical for regulating GTPase activity and viral target recognition.
To define domains of the human MxA GTPase involved in GTP hydrolysis and antiviral activity, we used two monoclonal antibodies (mAb) directed against different regions of the molecule. mAb 2C12 recognizes an epitope in the central interactive region of MxA, whereas mAb M143 is directed against the N-terminal G domain. mAb 2C12 greatly stimulated MxA GTPase activity, suggesting that antibody-mediated crosslinking enhances GTP hydrolysis. In contrast, monovalent Fab fragments of 2C12 abolished GTPase activity, most likely by blocking intramolecular interactions required for GTPase activation. Interestingly, intact IgG molecules and Fab fragments of 2C12 both prevented association of MxA with viral nucleocapsids and neutralized MxA antiviral activity in vivo. mAb M143 had no effect on MxA function, indicating that this antibody binds outside functional regions. These data demonstrate that the central region recognized by 2C12 is critical for regulation of GTPase activity and viral target recognition.
Flohr et al. (Tue,) reported a other. Monoclonal antibodies (mAb 2C12 and mAb M143) was evaluated on GTPase activity and antiviral activity. The central interactive region of human MxA GTPase, recognized by mAb 2C12, is critical for the regulation of GTPase activity and viral target recognition.