Os05g0108800
Os05g0108800 ,whose length is 1218bp from 470434 to 472245 in Chromosome 5,encodes the protein Cytochrome b5, containing 137 amino acid residues.
Contents
Annotated Information
By blast, we can find the sequence of Os05g0108800 is same to 'Cyto b5' in tobacco(query coverage is 100%), which encodes cytochrome b5, a rather conserved and essential protein.
Function
Cytochromes b5 are ubiquitous electron transport hemoproteins found in animals, plants, fungi and purple phototrophic bacteria. The microsomal and mitochondrial variants are membrane-bound, while bacterial and those from erythrocytes and other animal tissues are water-soluble. The family of cytochrome b5-like proteins includes (besides cytochrome b5 itself) hemoprotein domains covalently associated with other redox domains in flavocytochrome cytochrome b2 (L-lactate dehydrogenase; EC 1.1.2.3), sulfite oxidase (EC 1.8.3.1), plant and fungal nitrate reductases (EC 1.7.1.1, EC 1.7.1.2, EC 1.7.1.3), and plant and fungal cytochrome b5/acyl lipid desaturase fusion proteins. Cytochrome b5 is a small haem protein associated with the endoplasmic reticulum of higher plants, animals and fungi.[1][2] The role of cytochrome b5 in plants is involving in the desaturation of acyl-complex lipids in oilseeds.[3][4]A full-length clone encoding cytochrome b5 has been isolated from a tobacco leaf cDNA library in lambda gt11 by PCR using degenerate primers. Southern analysis indicated that more than one gene encodes cytochrome b5 in the tobacco genome. In vitro transcription and translation studies of the cDNA indicated that the protein inserts into the ER membrane by a non-SRP-mediated pathway and that the C-terminus of the protein is required for targeting and insertion.[5]
Cytochrome b5 in some biochemical reactions
EC 1.6.2.2 cytochrome-b5 reductase
NADH + H+ + 2 ferricytochrome b5 → NAD+ + 2 ferrocytochrome b5 EC 1.10.2.1 L-ascorbate—cytochrome-b5 reductase
L-ascorbate + ferricytochrome b5 → monodehydroascorbate + ferrocytochrome b5 EC 1.14.18.2 CMP-N-acetylneuraminate monooxygenase
CMP-N-acetylneuraminate + 2 ferrocytochrome b5 + O2 + 2 H+ → CMP-N-glycoloylneuraminate + 2 ferricytochrome b5 + H2O EC 1.14.19.1 stearoyl-CoA 9-desaturase
stearoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ → oleoyl-CoA + 2 ferricytochrome b5 + H2O EC 1.14.19.3 linoleoyl-CoA 9-desaturase
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ → γ-linolenoyl-CoA + 2 ferricytochrome b5 + H2O
Expression
3-D structures of a number of cytochrome b5 and yeast flavocytochrome b2 are known. The fold belongs to the α+β class, with two hydrophobic cores on each side of a β-sheet. The larger hydrophobic core constitutes the heme-binding pocket, closed off on each side by a pair of helices connected by a turn. The smaller hydrophobic core may have only a structural role and is formed by spatially close N-terminal and C-terminal segments. The two histidine residues provide the fifth and sixth heme ligands, and the propionate edge of the heme group lies at the opening of the heme crevice. Two isomers of cytochrome b5, referred to as the A (major) and B (minor) forms, differ by a 180° rotation of the heme about an axis defined by the α- and γ-meso carbons. In the developing tobacco seed the mRNA is abundant at very early stages (< 10 days after flowering).[5]
Evolution
In tobacco,this cDNA encodes a protein of 139 residues which exhibits a high degree of homology to other cytochrome b5s, the message for which is expressed predominantly in developing seeds and in pigmented flower tissue. Tauschii of agronomically relevant gene families that were associated with disease resistance, abiotic stress tolerance and grain quality. This draft genome sequence provides insight into the environmental adaptation of bread wheat and can aid in defining the large and complicated genomes of wheat species. You can also add sub-section(s) at will.
Labs working on this gene
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References
- ↑ Ozols J: Structure of cytochromeb 5 and its topology in the microsomal membrane. Biochim Biophys Acta 997 121–130 (1989).
- ↑ Rich PR, Bendall DS: Cytochrome components of plant microsomes. Eur J Biochem 55: 333–341 (1975).
- ↑ Kearns EV, Hugly S, Somerville CR: The role of cytochromeb 5 in Δ12 desaturation of oleic acid by microsomes of safflower (Carthamus tinctorius L.). Arch Biochem Biophys 284: 431–436 (1991).
- ↑ Smith MA, Cross AR, Jones OTG, Griffiths WT, Stymne S, Stobart AK: Electron transport components of the 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine 537–1 (Δ12-desaturase) in microsomal preparations from developing safflower (Carthamus tinctorius L.) cotyledons. Biochem J 272: 23–29 (1990).
- ↑ 5.0 5.1 Mark A. Smith, A. Keith Stobart, Peter R. Shewry, Johnathan A. Napier:Tobacco cytochromeb 5: cDNA isolation, expression analysis andin vitro protein targeting. Plant Molecular Biology: 527-537(1994)
