Globin-like protein superfamily; This globin-like domain superfamily contains a wide variety of all-helical proteins that bind porphyrins, phycobilins, and other non-heme cofactors, and play various roles in all three kingdoms of life, including sensors or transporters of oxygen. It includes the M/myoglobin-like, S/sensor globin, and T/truncated globin (TrHb) families, and the phycobiliproteins (PBPs). The M family includes chimeric (FHbs/flavohemoglobins) and single-domain globins: FHbs, Ngbs/neuroglobins, Cygb/cytoglobins, GbE/avian eye specific globin E, GbX/globin X, amphibian GbY/globin Y, Mb/myoglobin, HbA/hemoglobin-alpha, HbB/hemoglobin-beta, SDgbs/single-domain globins related to FHbs, and Adgb/androglobin. The S family includes GCS/globin-coupled sensors, Pgbs/protoglobins, and SSDgbs/sensor single domain globins. The T family is classified into three main groups: TrHb1s (N), TrHb2s (O) and TrHb3s (P). The M- and S families exhibit the canonical secondary structure of hemoglobins, a 3-over-3 alpha-helical sandwich structure (3/3 Mb-fold), built by eight alpha-helical segments (named A through H). For M family Adgbs, this globin domain is permuted, such that C-H are followed by A-B. The T family globins adopt a 2-on-2 alpha-helical sandwich structure, resulting from extensive and complex modifications of the canonical 3-on-3 alpha-helical sandwich that are distributed throughout the whole protein molecule. PBPs bind the linear tetrapyrrole chromophore, phycobilin, a prosthetic group chemically and metabolically related to iron protoporphyrin IX/protoheme. Examples of other globin-like domains which bind non-heme cofactors include those of the Bacillus anthracis sporulation inhibitors pXO1-118 and pXO2-61 which bind fatty acid and halide in vitro, and the globin-like domain of Bacillus subtilis RsbRA which is presumed to channel sensory input to the C-terminal sulfate transporter/ anti-sigma factor antagonist (STAT) domain. RsbRA is a component of the sigma B-activating stressosome, and a regulator of the RNA polymerase sigma factor subunit sigma (B).

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gi 930158445   1 GNHEAELKPLAQTHATKHKIPVKYLE 26
Cdd:cd08926   75 GSHEAELKPLAQTHATKHKIPPKYFE 100

Animal Myoglobins; Myoglobin (Mb) is a monomeric pentacoordinate heme-bound globin protein whose expression has long been considered limited to cardiomyocytes and striated skeletal muscle cell, however it has recently been found localized in a wide variety of tissues including smooth muscle cells. As a physiological catalyst, it can modulate reactive oxygen species levels, facilitate oxygen diffusion within the cell, and scavenge or generate NO depending on oxygen tensions within the cell. Through its NO dioxygenase and nitrite reductase activities, Mb regulates mitochondrial function in energy-demanding tissues.

                         10        20
                 ....*....|....*....|....*.
gi 930158445   1 GNHEAELKPLAQTHATKHKIPVKYLE 26
Cdd:cd08926   75 GSHEAELKPLAQTHATKHKIPPKYFE 100

Animal Myoglobins; Myoglobin (Mb) is a monomeric pentacoordinate heme-bound globin protein whose expression has long been considered limited to cardiomyocytes and striated skeletal muscle cell, however it has recently been found localized in a wide variety of tissues including smooth muscle cells. As a physiological catalyst, it can modulate reactive oxygen species levels, facilitate oxygen diffusion within the cell, and scavenge or generate NO depending on oxygen tensions within the cell. Through its NO dioxygenase and nitrite reductase activities, Mb regulates mitochondrial function in energy-demanding tissues.

                         10        20
                 ....*....|....*....|....*.
gi 930158445   1 GNHEAELKPLAQTHATKHKIPVKYLE 26
Cdd:cd08926   75 GSHEAELKPLAQTHATKHKIPPKYFE 100