The Diversity of Photosynthetic Cytochromes

Soluble domains of cytochrome c-556 and Rieske iron–sulfur protein from Chlorobaculum tepidum: Crystal structures and interaction analysis

“…Cytochrome (cyt) b c complexes are multi-subunit membrane-bound enzymes that play central roles in respiratory and photosynthetic electron transport chains functioning in the energy transducing systems of many organisms, including bacteria, archaea, eukaryotic mitochondria, and chloroplasts ( Majumder and Blankenship, 2016 ). They consist of at least three catalytic subunits: Rieske iron-sulfur protein (ISP) with a [2Fe–2S] cluster, cytochrome b with two b -type (one low potential ( b L ) and one high potential ( b H )) hemes, and cyt c 1 or f with a c -type heme.…”

New Structural and Mechanistic Insights Into Functional Roles of Cytochrome b559 in Photosystem II

“…Cytochrome (Cyt) b 559 is an essential component of the photosystem II (PSII) complex for proper functioning and assembly (reviews by Whitmarsh and Pakrasi, 1996 ; Stewart and Brudvig, 1998 ; Shinopoulos and Brudvig, 2012 ; Müh and Zouni, 2015 ; Chu and Chiu, 2016 ). Cyt b 559 is present in the PSII of all oxygenic photosynthetic organisms but is not found in anoxygenic type II reaction centers of photosynthetic bacteria (Majumder and Blankenship, 2015 ). Thus, Cyt b 559 likely co-evolved with the oxygen-evolving function of cyanobacteria.…”

“…Each subunit provides a histidine ligand for the non-covalently bound heme, which is located near the cytoplasmic side of PSII (Babcock et al, 1985 ). In contrast, most mono-heme cytochromes are made of a single polypeptide (Majumder and Blankenship, 2015 ). In addition, the Cyt b 559 in different PSII preparations features multiple distinct redox potential forms: high potential (HP) with Em + 370–400 mV, intermediate potential (IP) with Em of about 200 mV, and low potential (LP) with Em of about 0–80 mV (Ortega et al, 1988 ; Thompson et al, 1989 ; Kaminskaya et al, 1999 ; Roncel et al, 2001 ).…”

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“…Cytochrome (Cyt) b 559 is an essential component of the photosystem II (PSII) complex for proper functioning and assembly (reviews by Whitmarsh and Pakrasi, 1996;Stewart and Brudvig, 1998;Shinopoulos and Brudvig, 2012;Müh and Zouni, 2015;Chu and Chiu, 2016). Cytb 559 is present in the PSII of all oxygenic photosynthetic organisms but is not found in anoxygenic type II reaction centers of photosynthetic bacteria (Majumder and Blankenship, 2015). Thus, Cytb 559 likely co-evolved with the oxygen-evolving function of cyanobacteria.…”

“…Each subunit provides a histidine ligand for the non-covalently bound heme, which is located near the cytoplasmic side of PSII (Babcock et al, 1985). In contrast, most mono-heme cytochromes are made of a single polypeptide (Majumder and Blankenship, 2015). In addition, the Cytb 559 in different PSII preparations features multiple distinct redox potential forms: high potential (HP) with Em + 370-400 mV, intermediate potential (IP) with Em of about 200 mV, and low potential (LP) with Em of about 0-80 mV (Ortega et al, 1988;Thompson et al, 1989;Kaminskaya et al, 1999;Roncel et al, 2001).…”