Amino acid sequence alignments of α-
and β-polypeptides
in LH2 complexes for which a high-resolution 3D structure is available.
1, Rba. sphaeroides 2.4.1 (PDB 7PBW); 2, Rbl. acidophilus 10050 (PDB 1NKZ); 3, Rbl. acidophilus 7050 (PDB 1IJD); 4, Phs. molischianum DSM-119 (PDB 1LGH); and 5, Mch. purpuratum DSM-1591 (PDB 6ZXA). The sequences
shown in black are those reported and resolved in the PDB entries;
the blue characters in the α and β sequences for Rba. sphaeroides indicate those not modeled into
the density map. The sequences are aligned against the central His
residue (red) that coordinates the BChl a molecules
forming the main ring of pigments. The top set of numbers refers to
the residues in the Rba. sphaeroides LH2 complex. The lower set of numbers designates the His ligand
to the B850-type BChls (red) as 0 and counts forwards or backwards
from that point. This numbering system, from a central, conserved
residue, allows comparison of polypeptides of differing lengths and
from different bacteria. The LH2 oligomer sizes (number of αβ
subunits) for different strains are indicated.