Crystal structure of human CDK8/CYCC in complex with compound 1 (N-[3-tert-butyl-1-(4-methylphenyl)-1H-pyrazol-5-yl]-4-[2-({[3-tert-butyl-1-(4-methylphenyl)-1H-pyrazol-5-yl]carbamoyl}amino)ethyl]piperazine-1-carboxamide)