Sometimes, HSP70 is unable to effectively aid a protein in reaching its final 3-D structure; The main reason being the thermodynamic barriers for folding are too high for the chaperone to meet. Because the intracellular space is very crowded, sometimes proteins need an isolated space to prevent aberrant interactions between other proteins, which is provided by chaperonins or HSP60s . HSP60s are barrel shaped and suited to bind to the hydrophobic residues of proteins. Once a cap binds to the chaperonin, the protein is free within the barrel to undergo hydrophobic collapse and reach a stable conformation. Once the cap is removed, the protein can either be correctly folded and move on to perform its function or return to a HSP if it is still not folded accurately. These chaperones function to remove aggregation and significantly speed up protein folding.