Sandbox ggc6

You may include any references to papers as in: the use of JSmol in Proteopedia ^[1] or to the article describing Jmol ^[2] to the rescue.

Function

Focal Adhesion Kinase (FAK), also known as Protein Tyrosine Kinase 2, is an enzyme that can transfer a phosphate group from ATP to a protein in a cell and function as an "on/off" switch in cellular functions ^[3]. FAK allosteric inhibitors prevent tumors that can lead to different types of cancers due to cell proliferation.

Relevance

In order to develop potent and selective focal adhesion kinase (FAK) inhibitors, studies on pyrazolo[4,3-c][2,1]benzothiazines targeted for the FAK allosteric site were carried out ^[4]. This compound potentially possess two different binding modes: allosteric binding and hinge binding, and this hypothesis was also supported by the fact that FAK inhibitory potential of compound 22 under the high concentration of ATP was much weaker. The purpose was to facilitate pure allosteric inhibition of FAK by targeting the FAK allosteric site, demonstrating a potential of FAK allosteric inhibitors as antitumor agents. Kinase activity of FAK were selectively inhibited without affecting other kinases and the compound possessed significant FAK kinase inhibitory activities in cell free and cellular assays ^[5]. Phosphorylation of proteins by kinases is important in communicating signals within a cell and regulating cellular activity, such as cell division ^[6].

Structural highlights

. This scene shows the entire 4I4E structure of the PtK2 cell, showing alpha helix structure, beta sheets, and the backbone of the structure. When zooming in, the scene then shows how the compound of pyrazolo[4,3-c][2,1]benzothiazine inhibits the FAK allosteric site. The CPK ligand (compound 22) forms direct and/or water-mediated hydrogen bonds with Glu506, Ser509, and Arg514. These three sites are shown and labeled within the structure. The water mediated Hydrogen bond formed with Glu506 is also shown within the structure . Color Key: Cyan-Alpha Helix; Magenta-Beta Sheet; Yellow-Arg 514; Lime Green-All Glutamate; Dark Blue-Backbone/Main Chain; Maroon-All Lys; Black-Ser509; Orange-Cys502. The N-free pyrazole of 22 interacts with Glu500 and Cys502 in the hinge region by two hydrogen bonds ^[7]. .