Not without adding a crontroller card.
No G4 has SATA controllers as stock.
You can install a SATA PCI card from Sonnet or Firmtek in one of the PCI slots. But once you have the card, you can add any size of hard drive you want **Note there are a few specific models of Hitachi and Seagate hard drives that are incompatible with specific controllers, check the literature before buying.**
There are also bridge boards that go on the back of a drive to convert the drive's interface. I think these are a poor idea - there isn't physical room for them in the case, for one thing.