Structure of the F58W mutant of cytochromeb₅: the mutation leads to multiple conformations and weakens stacking interactions

Abstract

Phe58 of cytochrome b5 is involved in stacking interactions with heme and the axial ligand His63. To elucidate the contribution of the stacking interactions to protein stability, the crystal structures of the F58Y and F58W mutants were determined at high resolution. The structure of the F58Y mutant is basically the same as that of the wild-type protein. However, the mutation from Phe58 to Trp58 leads to difficulty in growing single crystals and results in a space-group change; the six molecules in the asymmetric unit form two groups that are related by a non-crystallographic twofold axis. The structure of F58W was determined using molecular replacement by making use of the non-crystallographic symmetry. The F58W mutation gives rise to multiple conformations of six side chains, a peptide linking two of the six residues and the extended propionic acid of the heme. The six molecules in the asymmetric unit of the F58W mutant structure are grouped into two types based on their conformations and one of the six molecules exhibits dual conformations. The stacking interactions are weakened owing to the increase/decrease of the angles between the indole ring of Trp58 and the His63/heme rings, which accounts for the lower stability of F58W compared with the wild-type protein.

Retracted: Dual‐Ion Stabilized Layered Structure of OVO for Zero‐Strain Potassium Insertion and Extraction

“…The crystal structure was further confirmed by XRD results (Figure 1d). The crystallinity of NaK(VO 3 ) 2 ‐V 2 O 5 has two Vanadium‐Based Oxides (NaK(VO 3 ) 2 : PDF#26‐1474 and V 2 O 5 : PDF#41‐1426) and is obviously lower than that in the literature, [ 13 ] which is related to the increased disorder of crystal structure caused by some vacancies, it can further accelerate the rapid transfer of electrons in the charging and discharging process due to the V 2 O 5 provide more space. X‐ray photoelectron spectroscopy (XPS) results confirmed that the electron cloud bias from electron‐rich V═O‐ and VOV‐ component to low binding energy field inducing the formation of built‐in electric field at the heterojunction interface (Figure 1e,f), which may accelerate the charge transfer dynamics at the heterogeneous interface.…”