Simplify the following text for a Grade 11 native English-speaking person.
Original: The first crystal structure of a macromolecule was solved in 1958 The Protein Data Bank ( PDB ) is a freely accessible repository for the structures of proteins and other biological macromolecules .
Simplified: The first crystal structure of a macromolecule was solved in 1958 A three-dimensional model of the myoglobin molecule obtained by X-ray analysis . The Protein Data Bank ( PDB ) is a freely accessible repository for the structures of proteins and other biological macromolecules .