Structural insight into the human mitochondrial tRNA purine N1-methyltransferase and ribonuclease P complexes by Oerum, S, Roovers, M, Rambo, R, Kopec, J, Bailey, H, Fitzpatrick, F, Newman, J, Newman, W, Amberger, A, Zschocke, J, Droogmans, L, Oppermann, U, Yue, W