Figure 4.

(a) Native-PAGE analysis reveals that FlvF mainly runs as a dimer at different concentrations, but a small fraction of tetramer is also observed. (b) The isologous dimer of FlvF is shown as a ribbon diagram with transparent surface representation. Each monomer is colored individually; monomers are oriented in antiparallel fashion. Red arrows indicate active sites. (c) Dimer interface of FlvF with interacting residues forming hydrogen bonds and salt bridges shown as sticks. Black dashed lines represent atomic distances between 2.6–3.5 Å and likely correspond to hydrogen bonds, taking into account the structure coordinate error of 0.37 Å.