Table 1.

Crystal structures of microbial rhodopsins

Protein/PDB ID	Source Organism	Expression Organism	Detergent	Oligomer	Crystal Environment
Bacteriorhodopsin/PDB: 1BRD	Halobacterium halobium	Halobacterium halobium	Octylglucoside, dodecyl trimethyl ammonium chloride	Trimer	2D crystal
Bacteriorhodopsin/PDB: 1KME	Halobacterium salinarum	Halobacierium salinarum	Octylglucoside	Monomer	Bicelle
Archaerhodopsin-3/PDB: 6GUY	Halorubrum sodomense	Halorubrum sodomense	Not published	Monomer	LCP
Halorhodopsin,/PDB: 5AHZ	Halobacierium salinarum	Halobacierium salinarum	n-Octyl-β-D-glucoside	Trimer	Detergent solution
Krokinobacter eikastus rhodopsin 2/PDB: 3X3C	Dokdonia eikasta	Escherichia coli	n-Dodecyl-β-D-maltopyranoside	Dimer	LCP
krokinobacter eikastus rhodopsin 2/PDB: 4XTN	Dokdonia eikasta	Escherichia coli	Triton X-100, n-Dodecyl-β-D-maltopyranoside	Pentamer	LCP
blue light-absorbing proteorhodopsin/PDB: 4JQ6	Uncultured bacterium	Escherichia coli	n-Decyl-D-maltoside	Hexamer	Bicelle