a, secondary structure of S. ruber sensory rhodopsin I
(SrSRI, SRU_2511). b, alignment of putative amino acid
sequences of SRIs reported so far
(29) with SrSRI.
Names of archaeal and bacterial sensory rhodopsins and sources from top are:
cso_Hva, Haloarcula vallismortis cruxsensory rhodopsin
(GenBank™ code: D83748); sop-F5R, H. salinarum strain Flx5R sR
(L05603); sop-SGl, Hb. sp. strain SGI sR (X70290); SRU_2511, S.
ruber strain DSM 13855 (3852586); SRU_2579, S. ruber strain DSM
13855 (3852268). Amino acid residues marked by an asterisk in helices
F and G are important residues for phototaxis in SRI. The amino acid residues
identified as necessary for function
(31) were conserved among them
except for a His residue (His-166 in HsSRI).