Role of tyrosine M210 in the initial charge separation of reaction centers of Rhodobacter sphaeroides

Femtosecond spectroscopy was used in combination with site-directed
mutagenesis to study the influence of tyrosine M210 (YM210) on the
primary electron transfer in the reaction center of Rhodobacter
sphaeroides. The exchange of YM210 to phenylalanine caused the time
constant of primary electron transfer to increase from 3.5 f 0.4 ps
to 16 f 6 ps while the exchange to leucine increased the time
constant even more to 22 f 8 ps. The results suggest that tyrosine
M210 is important for the fast rate of the primary electron
transfer.