Fig. 4. Key residues around the Trv. strain 970 RC special pair BChl a dimer.
a Top view of the BChl a dimer whose central Mg atoms are coordinated by the His residues in the L- and M-subunits. b Superposition of the residues in the RC L-subunits of Trv. strain 970 (magenta), Tch. tepidum (gray), and Rba. sphaeroides (gray) that form hydrogen bonds or interact with the BChl a molecule. c Superposition of the residues in the RC M-subunits of Trv. strain 970 (blue), Tch. tepidum (gray), and Rba. sphaeroides (gray) that form hydrogen bonds or interact with the BChl a molecule. All distances are in ångströms.