PDBsum entry 1aa4

Oxidoreductase

PDB id: 1aa4

Contents

Protein chain

291 a.a.

Ligands

HEM

Waters ×105

References listed in PDB file

Key reference

• Title: A ligand-Gated, Hinged loop rearrangement opens a channel to a buried artificial protein cavity.
• Authors: M.M.Fitzgerald, R.A.Musah, D.E.Mcree, D.B.Goodin.
• Ref.: Nat Struct Biol, 1996, 3, 626-631.
• PubMed id: 8673607

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.

Secondary reference #1

• Title: Small molecule binding to an artificially created cavity at the active site of cytochrome c peroxidase.
• Authors: M.M.Fitzgerald, M.J.Churchill, D.E.Mcree, D.B.Goodin.
• Ref.: Biochemistry, 1994, 33, 3807-3818. [DOI no: 10.1021/bi00179a004]
• PubMed id: 8142383

Secondary reference #2

• Title: The asp-His-Fe triad of cytochrome c peroxidase controls the reduction potential, Electronic structure, And coupling of the tryptophan free radical to the heme.
• Authors: D.B.Goodin, D.E.Mcree.
• Ref.: Biochemistry, 1993, 32, 3313-3324. [DOI no: 10.1021/bi00064a014]
• PubMed id: 8384877