Structure of the catalytic domain of human polo-like kinase 1.
Polo-like kinase 1 (Plk1) is an attractive target for the development of anticancer agents due to its importance in regulating cell-cycle progression. Overexpression of Plk1 has been detected in a variety of cancers, and expression levels often correlate with poor prognosis. Despite high interest in Plk1-targeted therapeutics, there is currently no structure publicly available to guide structure-based drug design of specific inhibitors. We determined the crystal structures of the T210V mutant of the kinase domain of human Plk1 complexed with the nonhydrolyzable ATP analogue adenylylimidodiphosphate (AMPPNP) or the pyrrolo-pyrazole inhibitor PHA-680626 at 2.4 and 2.1 A resolution, respectively. Plk1 adopts the typical kinase domain fold and crystallized in a conformation resembling the active state of other kinases. Comparison of the kinetic parameters determined for the (unphosphorylated) wild-type enzyme, as well as the T210V and T210D mutants, shows that the mutations primarily affect the kcat of the reaction, with little change in the apparent Km for the protein or nucleotide substrates (kcat = 0.0094, 0.0376, and 0.0049 s-1 and Km(ATP) = 3.2, 4.0, and 3.0 microM for WT, T210D, and T210V, respectively). The structure highlights features of the active site that can be exploited to obtain Plk1-specific inhibitors with selectivity over other kinases and Plk isoforms. These include the presence of a phenylalanine at the bottom of the ATP pocket, combined with a cysteine (as opposed to the more commonly found leucine) in the roof of the binding site, a pocket created by Leu132 in the hinge region, and a cluster of positively charged residues in the solvent-exposed area outside of the adenine pocket adjacent to the hinge region.
Kothe
Michael
M
Pfizer Global Research and Development, Research Technology Center, 620 Memorial Drive, Cambridge, Massachusetts 02139, USA.
Kohls
Darcy
D
Low
Simon
S
Coli
Rocco
R
Cheng
Alan C
AC
Jacques
Suzanne L
SL
Johnson
Theresa L
TL
Lewis
Cristina
C
Loh
Christine
C
Nonomiya
Jim
J
Sheils
Alissa L
AL
Verdries
Kimberly A
KA
Wynn
Thomas A
TA
Kuhn
Cyrille
C
Ding
Yuan-Hua
YH
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D020134:Catalytic Domain / Q000235:genetics; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004789:Enzyme Activation / Q000235:genetics; D004795:Enzyme Stability / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011487:Protein Conformation; D017510:Protein Folding; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000097869:Polo-Like Kinase 1
D018797:Cell Cycle Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1