Stabilization of photosystem II reaction centers: influence of bile salt detergents and low pH.

Rapid deterioration of samples is a major obstacle in research on the isolated reaction center of photosystem II. Its stability was tested systematically using a wide range of detergents, varying pH and temperature. Stability and activity did not depend on ionic properties of detergents or on critical micellar concentration. However, both were significantly increased by bile salt detergents in the dark as well as in the light. Low pH (5.5) and low temperature further improved stability. The results suggest that in particular the zwitterionic bile salt detergent, CHAPS, in pH 5.5 buffers is a very useful detergent and even superior to dodecylmaltoside for work with photosystem II reaction centers.