Hemoglobin, alpha 2

HBA2
Available structures
PDB	Ortholog search:PDBeRCSB
List of PDB id codes
	1A00,1A01,1A0U,1A0Z,1A3N,1A3O,1A9W,1ABW,1ABY,1AJ9,1B86,1BAB,1BBB,1BIJ,1BUW,1BZ0,1BZ1,1BZZ,1C7B,1C7C,1C7D,1CLS,1CMY,1COH,1DKE,1DXT,1DXU,1DXV,1FDH,1FN3,1G9V,1GBU,1GBV,1GLI,1GZX,1HAB,1HAC,1HBA,1HBB,1HBS,1HCO,1HDB,1HGA,1HGB,1HGC,1HHO,1IRD,1J3Y,1J3Z,1J40,1J41,1J7S,1J7W,1J7Y,1JY7,1K0Y,1K1K,1KD2,1LFL,1LFQ,1LFT,1LFV,1LFY,1LFZ,1LJW,1M9P,1MKO,1NEJ,1NIH,1NQP,1O1I,1O1J,1O1K,1O1L,1O1M,1O1N,1O1O,1O1P,1QI8,1QSH,1QSI,1QXD,1QXE,1R1X,1R1Y,1RPS,1RQ3,1RQ4,1RQA,1RVW,1SDK,1SDL,1SHR,1SI4,1THB,1UIW,1VWT,1XXT,1XY0,1XYE,1XZ2,1XZ4,1XZ5,1XZ7,1XZU,1XZV,1Y01,1Y09,1Y0A,1Y0C,1Y0D,1Y0T,1Y0W,1Y22,1Y2Z,1Y31,1Y35,1Y45,1Y46,1Y4B,1Y4F,1Y4G,1Y4P,1Y4Q,1Y4R,1Y4V,1Y5F,1Y5J,1Y5K,1Y7C,1Y7D,1Y7G,1Y7Z,1Y83,1Y85,1Y8W,1YDZ,1YE0,1YE1,1YE2,1YEN,1YEO,1YEQ,1YEU,1YEV,1YFF,1YG5,1YGD,1YGF,1YH9,1YHE,1YHR,1YIE,1YIH,1YVQ,1YVT,1YZI,1Z8U,2D5Z,2D60,2DN1,2DN2,2DN3,2DXM,2H35,2HBC,2HBD,2HBE,2HBF,2HBS,2HCO,2HHD,2HHE,2M6Z,2W6V,2W72,2YRS,3B75,3D17,3D7O,3DUT,3HXN,3IA3,3IC0,3IC2,3KMF,3NL7,3NMM,3ODQ,3ONZ,3OO4,3OO5,3OVU,3P5Q,3QJB,3QJC,3QJD,3QJE,3R5I,3S48,3S65,3S66,3SZK,3WCP,3WHM,4FC3,4HHB,4IJ2,4L7Y,4M4A,4M4B,4MQC,4MQG,4MQH,4MQI,4MQJ,4MQK,4N7N,4N7O,4N7P,4N8T,4NI0,4NI1,4ROL,4ROM,4WJG,4X0L,4XS0,6HBW,5E29,5E6E,5EE4,5HU6,5JDO,5KDQ,5E83,%%s1Y01,1Z8U,1BZ1
Identifiers
Aliases	HBA2,HBA-T2, HBH, Hemoglobin, alpha 2, hemoglobin subunit alpha 2, ECYT7
External IDs	OMIM:141850;MGI:96015;HomoloGene:469;GeneCards:HBA2;OMA:HBA2 - orthologs
Gene location (Human)
Chr.	Chromosome 16 (human)
End	173,710bp
Gene location (Mouse)
Chr.	Chromosome 11 (mouse)
End	32,234,465bp
RNA expressionpattern
	Top expressed in
	monocyte; ; blood; ; bone marrow; ; bone marrow cells; ; placenta; ; spleen; ; apex of heart; ; ganglionic eminence; ; muscle of thigh; ; olfactory zone of nasal mucosa;
	Top expressed in
	bone marrow; ; spleen; ; lung; ; yolk sac; ; neural tube; ; mesencephalon; ; heart; ; cerebellar cortex; ; genital tubercle; ; zone of skin;
	More reference expression data
	n/a
Gene ontology
Molecular function	iron ion binding; oxygen binding; peroxidase activity; oxygen carrier activity; metal ion binding; protein binding; heme binding; haptoglobin binding; organic acid binding;
Cellular component	cytosol; endocytic vesicle lumen; blood microparticle; membrane; extracellular region; cytosolic small ribosomal subunit; hemoglobin complex; extracellular exosome; haptoglobin-hemoglobin complex; extracellular space;
Biological process	positive regulation of cell death; protein heterooligomerization; oxygen transport; receptor-mediated endocytosis; bicarbonate transport; hydrogen peroxide catabolic process; response to hydrogen peroxide; cellular oxidant detoxification; transport;
	Sources:Amigo/QuickGO
Orthologs
	3040
	15122
	ENSG00000188536
	ENSMUSG00000069919
	P69905
	Q91VB8
	NM_000517
	NM_008218
	NP_000508; NP_000508.1; NP_000549.1
	NP_001077424
	Wikidata
View/Edit Human	View/Edit Mouse

Hemoglobin, alpha 2^[5]also known asHBA2is agenethat in humans codes for the alpha globin chain ofhemoglobin.^[6]^[7]

Function

The human alpha globin gene cluster is located on chromosome 16 and spans about 30 kb, including seven alpha like globin genes and pseudogenes: 5'-HBZ- HBZP1 -HBM- HBAP1 - HBA2 -HBA1-HBQ1-3'. The HBA2 (α₂) andHBA1(α₁) coding sequences are identical. These genes differ slightly over the 5' untranslated regions and the introns, but they differ significantly over the 3' untranslated regions.

Protein

Two alpha chains plus two beta chains constituteHbA,which in normal adult life accounts for about 97% of the totalhemoglobin;alpha chains combine with delta chains to constituteHbA-2,which withHbF(fetal hemoglobin), composed of alpha and gamma chains, make up the remaining 3% of adult hemoglobin.

Clinical significance

Alpha-thalassemiasmost commonly result from deletions of any of the four alpha alleles, although some alpha thalassemias have been reported that are due to mutations other than deletion. Deletion of 1 or 2 alleles is clinically silent. Deletion of 3 alleles causes HbH disease, resulting in anemia and hepatosplenomegaly. Deletion of all 4 alleles is lethal because it renders the body unable to make fetal hemoglobin (HbF), adult hemoglobin (HbA) or adult variant hemoglobin (HbA2), and results inhydrops fetalis.^[8]

References

^^a ^b ^cGRCh38: Ensembl release 89: ENSG00000188536–Ensembl,May 2017
^^a ^b ^cGRCm38: Ensembl release 89: ENSMUSG00000069919–Ensembl,May 2017
^"Human PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
^"HBA2 gene: MedlinePlus Genetics".
^Liebhaber SA, Goossens MJ, Kan YW (Dec 1980)."Cloning and complete nucleotide sequence of human 5'-alpha-globin gene".Proceedings of the National Academy of Sciences of the United States of America.77(12): 7054–8.Bibcode:1980PNAS...77.7054L.doi:10.1073/pnas.77.12.7054.PMC350439.PMID 6452630.
^Higgs DR, Vickers MA, Wilkie AO, Pretorius IM, Jarman AP, Weatherall DJ (Apr 1989)."A review of the molecular genetics of the human alpha-globin gene cluster".Blood.73(5): 1081–104.doi:10.1182/blood.V73.5.1081.1081.PMID 2649166.
^"Entrez Gene: HBA2 hemoglobin, alpha 2".

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