A lattice model of protein conformation and dynamics is used to explore the requirements for the de novo folding from an arbitrary random coil state of idealized models of four and six-member beta-barrels. A number of possible conjectures for the factors giving rise to the structural uniqueness of globular proteins are examined. These include the relative role of generic hydrophilic/hydrophobic amino acid patterns, the relative importance of the specific identity of the hydrophobic amino acids that form the core of the protein and the possible role played by polar groups in destabilizing alternative, misfolded conformations. These studies may also provide some insights into the relative importance of short range interactions, cooperative hydrogen bonding and tertiary interactions in determining the uniqueness of the native state, as well as the cooperativity of the folding process. Thus, these simulations may provide guidelines for the early stages of the protein design process. Possible applications to the general protein folding problem are also briefly discussed.