EC Number   |
General Information |
Reference |
|---|
   2.7.11.7 | evolution |
alpha-kinases transfer the gamma-phosphate of ATP to protein substrates through an aspartylphosphate intermediate |
723767 |
| 2.7.11.7 | evolution |
myosin II heavy chain kinase A is a member of the atypical alpha-kinase family |
722716 |
| 2.7.11.7 | malfunction |
removal of the N-rich region severely compromises MHC phosphorylation by the catalytic domain. Removal of both the N-rich and WD-repeat domains renders the catalytic domain barely able to phosphorylate MHC above detectable levels, whereas the truncation containing the N-rich region can still use MHC as a substrate, albeit at about 30% of that displayed by the full-length kinase. But the innate kinase activity of the catalytic domain is not lost upon removal of the N-rich region and/or the WD-repeat domain of MHCK-B since all three versions of MHCK-B phosphorylated MH-1 peptide to the same level |
721946 |
| 2.7.11.7 | malfunction |
the catalytic activity of A-CAT, the alpha-kinase domain of MHCKA comprising residues 552-841, is severely inhibited by the removal of a disordered C-terminal tail residues 806-841 |
722716 |
| 2.7.11.7 | more |
ADP is bound at the active site and invariant Asp766 at the active site is phosphorylated in the crysstallized MHCK A. The aspartylphosphate group is exposed to the solvent within an active-site pocket that might function as a docking site for substrates. Access to the aspartylphosphate is regulated by a conformational switch in a loop that binds to a Mg2+ ion, providing a mechanism that allows alpha-kinases to sense and respond to local changes in Mg2+ concentration. Access to the active-site pocket was regulated by a C-terminal glycine-rich loop that bound to Mg2+ and switched between two distinct conformations. The invariant Asp766 residue is located at the center rear of the active site where it interacted with phosphate, the alpha-phosphate of AMP, and Mg2+ in the active-site pocket |
723767 |
| 2.7.11.7 | more |
mechanism for targeting myosin II heavy chain phosphorylation by myosin heavy chain kinase B, overview. An intrinsically unstructured, and asparagine-rich, region of a MHCK-B can mediate specific targeting of the kinase to phosphorylate myosin II heavy chain involving a direct binding interaction with myosin II filaments, while the the WD repeat domain is not absolutely required in MHCK-B substrate targeting, in contrast to isozyme MHCK-A. The N-rich region facilitates phosphorylation of MHC by binding directly to myosin II filaments |
721946 |
| 2.7.11.7 | more |
the phosphate-pocket functions as a positive allosteric binding site, the phosphorylated Thr825 activates alpha-kinase domain by providing a covalently tethered ligand for the phosphate-pocket, mechanism modeling |
722716 |
| 2.7.11.7 | physiological function |
heavy chain phosphorylation plays a central role in regulating myosin II bipolar filament assembly in Dictyostelium |
721946 |
| 2.7.11.7 | physiological function |
myosin II heavy chain kinase A, MHCK A, disrupts the assembly and cellular activity of bipolar filaments of myosin II by phosphorylating sites within its alpha-helical, coiled-coil tail |
723767 |
| 2.7.11.7 | physiological function |
the enzyme phosphorylates sites in the myosin II tail that block filament assembly |
722716 |
