A ligand-gated, hinged loop rearrangement opens a channel to a buried artificial protein cavity.
Fitzgerald, M.M., Musah, R.A., McRee, D.E., Goodin, D.B.(1996) Nat Struct Biol 3: 626-631
- PubMed: 8673607 
- DOI: https://doi.org/10.1038/nsb0796-626
- Primary Citation of Related Structures:  
1AA4, 1AES, 1AET, 1AEU, 1CCI, 1RYC - PubMed Abstract: 
Conformational changes that gate the access of substrates or ligands to an active site are important features of enzyme function. In this report, we describe an unusual example of a structural rearrangement near a buried artificial cavity in cytochrome c peroxidase that occurs on binding protonated benzimidazole. A hinged main-chain rotation at two residues (Pro 190 and Asn 195) results in a surface loop rearrangement that opens a large solvent-accessible channel for the entry of ligands to an otherwise inaccessible binding site. The trapping of this alternate conformational state provides a unique view of the extent to which protein dynamics can allow small molecule penetration into buried protein cavities.
Organizational Affiliation: 
Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037, USA.