KcsA High Resolution Crystal Structure

 

 

KScAHR1

KcsA (yellow) was crystallized as a complex with an antibody Fab fragment (blue). One Fab fragment is bound to the extracellular-facing turret on each K+ channel subunit. Two subunits and attached Fab fragments viewed perpendicular to the four-fold axis. The transmembrane outer and inner helices are labelled. The asterisk denotes the location of the central cavity, below the selectivity filter (red).

 

 

 

 

 

 

 

 

 

 

 

 

 

KCsAHR2

 

 

 

 

 

 

 

 

A) K+ ions are partially dehydrated before entering selectivity filter.

 

 

 

 

 

 

 

 

B) K+ ions are fully dehydrated in selectivity filter.

 

 

 

 

 

 

 

 

 

C) K+ ions are fully rehydrated in cavity.

 

 

Yufeng, Z., Morais-Cabral, J.H., Kaufman, A., MacKinnon, R. (2001). Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 Å resolution. Nature, 414, 43-48. doi: 10.1038/35102009

  KcsA (yellow) was crystallized as a complex with an antibody Fab fragment (blue). One Fab fragment is bound to the extracellular-facing turret on each K+ channel subunit. Two subunit