Subunit M of bacterial photosynthetic reaction center; Bacterial photosynthetic reaction center (RC) complex, subunit M. The bacterial photosynthetic reaction center couples light-induced electron transfer with pumping protons across the membrane using reactions involving a quinone molecule (QB) that binds two electrons and two protons at the active site. The reaction center consists of three membrane-bound subunits, designated L, M, and H, plus an additional extracellular cytochrome subunit. The L and M subunits are arranged around an axis of 2-fold rotational symmetry perpendicular to the membrane, forming a scaffold that maintains the cofactors in a precise configuration. The L and M subunits have both sequence and structural similarity, suggesting a common evolutionary origin. The L and M subunits bind noncovalently to the nine cofactors in 2-fold symmetric branches: four bacteriochlorophylls (Bchl), two bacteriopheophytins (Bphe), two ubiquinone molecules (QA and QB), and a non-heme iron. Two Bchls on the periplasmic side of the membrane form the 'special pair' or dimer which is the primary electron donor for the photosynthetic reactions. The electron transfer reaction proceeds from the dimer to an intermediate acceptor (PA), a primary quinone (QA), and a secondary quinone (QB). Protons are translocated from the bacterial cytoplasm to the periplasmic space, generating an electrochemical gradient of protons (the protonmotive force) that can be used to power reactions such as ATP synthesis. The RC complex is found in photosynthetic bacteria, such as purple bacteria and other proteobacteria species.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 482668007   1 PHLDWTAAFSLRYGNLFYNPFHMLSIAFLYGSALLFAMHGATILAVSRFGGEREIEQITDRGTASERAALFWRWTMG 77
Cdd:cd09291  170 PHLDWTNAFSIRYGNFYYNPFHMLSIAFLYGSTLLFAMHGATILAVSRFGGEREIEQITDRGTATERAQLFWRWTMG 246

Photosynthetic reaction centre protein;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 482668007    1 PHLDWTAAFSLRYGNLFYNPFHMLSIAFLYGSALLFAMHGATILAVSRFGGEREIEQITDRGTASERAALFWRWTMG 77
Cdd:pfam00124 133 PHLDWTSNFSYRYGNFLYNPFHMLGIAFLFGSALLLAMHGALVLSVLRPGGTREVESINDRGTAGEREATFWRWTMG 209

Subunit M of bacterial photosynthetic reaction center; Bacterial photosynthetic reaction center (RC) complex, subunit M. The bacterial photosynthetic reaction center couples light-induced electron transfer with pumping protons across the membrane using reactions involving a quinone molecule (QB) that binds two electrons and two protons at the active site. The reaction center consists of three membrane-bound subunits, designated L, M, and H, plus an additional extracellular cytochrome subunit. The L and M subunits are arranged around an axis of 2-fold rotational symmetry perpendicular to the membrane, forming a scaffold that maintains the cofactors in a precise configuration. The L and M subunits have both sequence and structural similarity, suggesting a common evolutionary origin. The L and M subunits bind noncovalently to the nine cofactors in 2-fold symmetric branches: four bacteriochlorophylls (Bchl), two bacteriopheophytins (Bphe), two ubiquinone molecules (QA and QB), and a non-heme iron. Two Bchls on the periplasmic side of the membrane form the 'special pair' or dimer which is the primary electron donor for the photosynthetic reactions. The electron transfer reaction proceeds from the dimer to an intermediate acceptor (PA), a primary quinone (QA), and a secondary quinone (QB). Protons are translocated from the bacterial cytoplasm to the periplasmic space, generating an electrochemical gradient of protons (the protonmotive force) that can be used to power reactions such as ATP synthesis. The RC complex is found in photosynthetic bacteria, such as purple bacteria and other proteobacteria species.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 482668007   1 PHLDWTAAFSLRYGNLFYNPFHMLSIAFLYGSALLFAMHGATILAVSRFGGEREIEQITDRGTASERAALFWRWTMG 77
Cdd:cd09291  170 PHLDWTNAFSIRYGNFYYNPFHMLSIAFLYGSTLLFAMHGATILAVSRFGGEREIEQITDRGTATERAQLFWRWTMG 246

Photosynthetic reaction centre protein;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 482668007    1 PHLDWTAAFSLRYGNLFYNPFHMLSIAFLYGSALLFAMHGATILAVSRFGGEREIEQITDRGTASERAALFWRWTMG 77
Cdd:pfam00124 133 PHLDWTSNFSYRYGNFLYNPFHMLGIAFLFGSALLLAMHGALVLSVLRPGGTREVESINDRGTAGEREATFWRWTMG 209

D1, D2 subunits of photosystem II (PSII); M, L subunits of bacterial photosynthetic reaction center; This protein superfamily contains the D1, D2 subunits of the photosystem II (PS II) and the M, L subunits of the bacterial photosynthetic reaction center (RC). These four proteins are highly homologous and share a common fold. PS II is a multi-subunit protein found in the photosynthetic membranes of plants, algae, and cyanobacteria. It utilizes light-induced electron transfer and water-splitting reactions to produce protons, electrons, and molecular oxygen. The protons generated are instrumental in ATP formation. Bacterial photosynthetic reaction center (RC) complex is found in photosynthetic bacteria, such as purple bacteria and other proteobacteria species. It couples light-induced electron transfer to proton pumping across the membrane by reactions of a quinone molecule (QB) that binds two electrons and two protons at the active site. Protons are translocated from the bacterial cytoplasm to the periplasmic space, generating an electrochemical gradient of protons (the protonmotive force) that can be used to power reactions such as the synthesis of ATP.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 482668007   2 HLDWTAAFSLRYGNLFYNPFHMLSIAFLYGSALLFAMHGATILAVSRFGGEREIEQITDRGTASERAALFWRWTMG 77
Cdd:cd09223   94 HLDWVNNFQYEHNNWHYNPFHMLGVAFVFGGALLCAMHGALVLSVLNPEGEETEGQEAEEYNTAEHANYFWRDIFG 169

Subunit L of bacterial photosynthetic reaction center; Bacterial photosynthetic reaction center (RC) complex, subunit L. The bacterial photosynthetic reaction center couples light-induced electron transfer with pumping protons across the membrane using reactions involving a quinone molecule (QB) that binds two electrons and two protons at the active site. The reaction center consists of three membrane-bound subunits, designated L, M, and H, plus an additional extracellular cytochrome subunit. The L and M subunits are arranged around an axis of 2-fold rotational symmetry perpendicular to the membrane, forming a scaffold that maintains the cofactors in a precise configuration. The L and M subunits have both sequence and structural similarity, suggesting a common evolutionary origin. The L and M subunits bind noncovalently to the nine cofactors in 2-fold symmetric branches: four bacteriochlorophylls (Bchl), two bacteriopheophytins (Bphe), two ubiquinone molecules (QA and QB), and a non-heme iron. Two Bchls on the periplasmic side of the membrane form the 'special pair' or dimer which is the primary electron donor for the photosynthetic reactions. The electron transfer reaction proceeds from the dimer to an intermediate acceptor (PA), a primary quinone (QA), and a secondary quinone (QB). Protons are translocated from the bacterial cytoplasm to the periplasmic space, generating an electrochemical gradient of protons (the protonmotive force) that can be used to power reactions such as ATP synthesis. The RC complex is found in photosynthetic bacteria, such as purple bacteria and other proteobacteria species.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 482668007   1 PHLDWTAAFSLRYGNLFYNPFHMLSIAFLYGSALLFAMHGATILAVSRFGGEREIE 56
Cdd:cd09290  153 SHLDWVSNFGYQYLNFHYNPAHMIAITFLFTNTLALSMHGSLILSAANPKKGEPVK 208

D2 subunit of photosystem II (PS II); Photosystem II (PS II), D2 subunit. PS II is a multi-subunit protein found in the photosynthetic membranes of plants, algae, and cyanobacteria. It utilizes light-induced electron transfer and water-splitting reactions to produce protons, electrons, and molecular oxygen. The protons generated are instrumental in ATP formation. Molecular dioxygen is released as a by-product. PS II can be described as containing two parts: the photochemical part and the catalytic part. The photochemical portion promotes the fast, efficient light-induced charge separation and stabilization that occur when light is absorbed by chlorophyll. The catalytic portion, where water is oxidized, involves a cluster of Mn ions close to a redox-active tyrosine residue. The Mn cluster and its ligands form a functional unit called the oxygen-evolving complex (OEC) or the water-oxidizing complex (WOC). The D1 and D2 subunits are a pair of intertwined polypeptides. They contain all the cofactors involved directly in water oxidation and plastoquinone reduction. D1 and D2 are highly homologous and are also similar to the L and M proteins in bacterial photosynthetic reaction centers.

                         10        20        30
                 ....*....|....*....|....*....|.
gi 482668007  13 YGNLFYNPFHMLSIAFLYGSALLFAMHGATI 43
Cdd:cd09288  175 FHNWTLNPFHMMGVAGVLGAALLCAIHGATV 205

photosystem II protein D2

                         10        20
                 ....*....|....*....|....*....
gi 482668007  15 NLFYNPFHMLSIAFLYGSALLFAMHGATI 43
Cdd:CHL00004 191 NWTLNPFHMMGVAGVLGAALLCAIHGATV 219

photosystem Q(B) protein; Provisional

                         10        20
                 ....*....|....*....|....*....
gi 482668007  15 NLFYNPFHMLSIAFLYGSALLFAMHGATI 43
Cdd:PLN00056 191 NILMHPFHMLGVAGVFGGSLFSAMHGSLV 219