6OY6|1|B|MG|1601 MG ion 6OY6|1|D|MG|1601 MG ion 6OY6|1|D|MG|1605 MG ion 6OY6|1|D|ZN|1602 ZN ion 6OY6|1|D|ZN|1603 ZN ion 6OY6|1|D|GTP|1604 GTP rna