FAVORED CARBONYL BINDING REGIONS AROUND THE Q(A), AND Q(B) SITES OF RHODOPSEUDOMONAS-VIRIDIS

The factors governing quinone protein binding in the photosynthetic ba cterium Rps. viridis are investigated via use of empirical intermolecu lar energy calculations using the GRID method (PJ Goodford (1985) J Me d Chem 28:849-854). A probe atom corresponding to a carbonyl oxygen at om is used to investigate regions exhibiting preference for carbonyl b inding in the Q(A) and Q(B) sites of Rps. viridis. Two distinct region s at the top and bottom of the sites are revealed to be most favourabl e for carbonyl binding. Overlay of the crystallographically determined positions for the quinone carbonyl groups shows that they lie within the regions predicted theoretically. The method is also shown to be ab le to give qualitative insight into the affect of amino acid mutations of quinone binding.