Probing the function of heme distortion in the H-NOX family.

摘要: Hemoproteins carry out diverse functions utilizing a wide range of chemical reactivity while employing the same heme prosthetic group. It is clear from high-resolution crystal structures and biochemical studies that protein-bound hemes are not planar adopt conformations. The structure an H-NOX domain Thermoanaerobacter tengcongensis (Tt H-NOX) contains most distorted reported to date. In this study, Tt was engineered flatter by mutating proline 115, conserved residue in family, alanine. Decreasing distortion increases affinity for oxygen decreases reduction potential iron. Additionally, flattening associated with significant shifts N-terminus protein. These results show link between conformation demonstrate important determinant maintaining properties proteins.