Fig. 3: Structure of LH2 in the Hlr. halophila LH1–LH2 co-complex.
From: A distinct double-ring LH1–LH2 photocomplex from an extremophilic phototroph
a Top view of the LH2 complex viewing from the periplasmic side. Polypeptides are shown by cylindrical cartoons and pigments are shown by sticks. Phosphatidylglycerols in the central hole are shown by thin sticks (wheat). Color scheme: α-polypeptides, cyan; β-polypeptides, magenta; BChl a, red; carotenoids, yellow. b Tilted view of the pigments in the LH2 with representative distances (in Å) between the BChls a. For clarity, phytol chains are omitted. c The BChl a-binding sites in an LH2 subunit. Half of the dimeric BChls a form hydrogen bonds with α-Tyr41 while half lack such hydrogen bonds. The monomeric BChls a are coordinated by α-Met1 and form hydrogen bonds with β-Arg38. d Overlapping view of the Hlr. halophila LH2 (colored) and that of Rbl. acidophilus 10050 (gray, PDB: 1NKZ) by superposition of Cα carbons. e Sequences of α- and β-polypeptides. Red letters: BChl a-coordinating residues; magenta letter: hydrogen-bonding residue; light-gray letters: invisible residues.
