δ-globin

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Δ globin
Δ globin
Structure of the HBD protein
Identifier
Gene name (s) HBD
External IDs

δ-globin , delta-globin , or hemoglobin delta chain is a protein from the globins family , the 147 amino acid long polypeptide chain of which binds a heme as a cofactor and is thus part of the protein complex of hemoglobin A 2 (Hb A 2 ), which Hemoglobin subunit delta ( HBD ).

The δ-globin , making it part of a hemoglobin variant that the adult human for the transport of oxygen is formed. Encodes it by the HBD - gene , which in the gene cluster of the β-globin locus (with the sequence 5 '- hbe1 - hbg2 - hbg1 - HBD - HBB 3 -' ) on chromosome 11 is located. The expression of these very similar genes is regulated here via a common control region and is different depending on development. Depending on the development phase or cell environment, protein biosynthesis can be initiated by the corresponding ε , γ , δ or β globins . These proteins differ from one another only in a few amino acids of their 147 AA long chain; however, the hemoglobins made up of them show differences in oxygen - binding capacity .

function

After birth, the formation of red blood cells ( erythropoiesis ) takes place primarily in the bone marrow and the hemoglobins of adults, called "adult hemoglobins", are predominantly formed. Like fetal hemoglobin (HbF), these consist of four subunits that are identical in pairs. Two of them are also alpha- (α), but the other two are not gamma chains, but products of the beta gene ( HBB ) or the delta gene ( HBD ). Of two pairs with α-globin and β-globin , the sets HbA (α together 2 β 2 ); in normal adult life it makes up approximately 97% of total hemoglobin. The HbA 2 (α 2 δ 2 ) consists of two alpha and two delta subunits ; together with HbF (α 2 γ 2 ) it makes up the remaining 3% of adult hemoglobin.

Clinical significance

Mutations in the HBD gene for δ-globin have been implicated in delta thalassemia.

See also

Individual evidence

  1. ↑ Entrez Gene: HBE1 hemoglobin, epsilon 1 . Retrieved May 19, 2012.
  2. ↑ Higgs DR, Vickers MA, Wilkie AO, Pretorius IM, Jarman AP, Weatherall DJ: A review of the molecular genetics of the human alpha-globin gene cluster . In: Blood . 73, No. 5, May 1989, pp. 1081-104. PMID 2649166 .
  3. ↑ Entrez Gene: HBD hemoglobin, delta . Retrieved May 19, 2012.

literature

  • Schillirò G, Russo-Mancuso G, Dibenedetto SP, et al. : Six rare hemoglobin variants found in Sicily. . In: Hemoglobin . 15, No. 5, 1992, pp. 431-7. doi : 10.3109 / 03630269108998862 . PMID 1802885 .
  • Collins FS, Weissman SM: The molecular genetics of human hemoglobin. . In: ... Prog Nucleic Acid Res Mol Biol. . 31, 1985, pp. 315-462. PMID 6397774 .
  • Giardina B, Messana I, Scatena R, Castagnola M: The multiple functions of hemoglobin. . In: Crit. Rev. Biochem. Mol. Biol . 30, No. 3, 1995, pp. 165-96. doi : 10.3109 / 10409239509085142 . PMID 7555018 .