Crystallization and preliminary crystallographic analysis of 3'-aminoglycoside kinase type IIIa complexed with a eukaryotic protein kinase inhibitor, CKI-7.

3'-Aminoglycoside kinase type IIIa [APH(3')-IIIa] catalyzes the transfer of gamma-phosphate from ATP to the 3'-hydroxyl of many aminoglycoside antibiotics, abolishing their bactericidal effects. Despite very low sequence identity, APH(3')-IIIa and eukaryotic protein kinases share structural and functional similarities, including a sensitivity to isoquinolinsulfonamide-type inhibitors. APH(3')-IIIa has been cocrystallized with CKI-7, a casein kinase 1 inhibitor. These crystals were grown using PEG 3000 as precipitant and required consecutive cycles of microseeding. Data were collected to 2.5 A. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 49.84, b = 91.90, c = 131.2 A.