test</scene’>

Function

Disease

Relevance

Structural highlights

H and O channels

Figure 3

The hydrogen and oxygen channels (Fig. 3) are essential for H⁺ and O₂ molecules to reach the active site of bd oxidase. A proton motive force generated by the oxidase^[1] allows protons from the cytoplasm flow through a water-filled hydrophilic H-channel entering at D119^A and moving past K57^A, K109^B, D105^B, Y379^B, and D58^{B [2]} where they can be transferred to the active site with the help of the conserved residues S108^A, E107^A, and S140^A. A smaller o-channel also exists that transitions from hydrophobic to hydrophilic as it gets closer to the active site. This channel allows oxygen to reach the active site, starting near W63 in CydB and passing by L101^B, I114^A, and E99^A. The o-channel channel is approximately 1.5 Å in diameter, which may help with selectivity. Inhbitors that target the o-channel by blocking its entrance are quite effective by preventing the reduction of oxygen to water.

Interestingly, the o-channel does not exist in the bd oxidase of Geobacillus thermodenitrificans; instead, oxygen binds directly to the active site. The CydS subunit found in E. coli blocks this alternate oxygen entry site, which allows oxygen to travel through the o-channel. The presence of an o-channel affects oxidase activity, as the E. coli oxidase acts as a "true" oxidase, while the G. th oxidase contributes more to detoxification.

Hemes

Relevance

This is a sample scene created with SAT to by Group, and another to make of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.