Title
Ubiquitin-associated domain of MARK4 provides stability at physiological pH
Author
Farha Naz, Neha Sami, Asimul Islam, Faizan Ahmad, Md. Imtaiyaz Hassan
Year
2016
Journal
International Journal of Biological Macromolecules
Abstract
Microtubule affinity regulatory kinase 4 (MARK4) belongs to the family of AMP-activated protein kinase. It phosphorylates microtubule associated proteins at specific sites (Serine in KXGS motifs) in the microtubule-binding repeats. In our previous studies, two constructs, namely, kinase domain with 59 residues of N-terminal residues (residues 1-310) and only kinase domain (residues 59-310) of MARK4 show aggregation at physiological pH. However, these two constructs were stable at extremes of pH conditions. Now the question arises: how is MARK4 stable at physiological pH in-vivo? To answer this question, we have successfully cloned, expressed, and purified UBA-domain along with the kinase domain of MARK4 and performed spectroscopic measurements and activity assays. We observed a pronounced secondary and tertiary structure and ATPase activity in the MARK4 at physiological pH. In conclusion, UBA domain may be important to maintain the structure, stability and activity of MARK4 under physiological conditions.
Instrument
J-1500
Keywords
Circular dichroism, Secondary structure, Chemical stability, Biochemistry