HBA2

This article is about a gene. For the similarly named Hemoglobin tetramer, HbA2, see Hemoglobin A2.

Hemoglobin, alpha 2
PDB rendering based on 1hbb.
Available structures PDB 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, 2HHB, 2HHD, 2HHE, 2W6V, 2W72, 2YRS, 3B75, 3D17, 3D7O, 3DUT, 3HHB, 3HXN, 3IA3, 3IC0, 3IC2, 3KMF, 3NL7, 3NMM, 4HHB, 6HBW
Identifiers
Symbols	HBA2; CD31; MGC126895; MGC126897
External IDs	OMIM: 141850 MGI: 96015 HomoloGene: 469 GeneCards: HBA2 Gene
Gene Ontology Molecular function • peroxidase activity • oxygen transporter activity • protein binding • oxygen binding • heme binding • haptoglobin binding • metal ion binding Cellular component • hemoglobin complex • hemoglobin complex • cytosolic small ribosomal subunit • haptoglobin-hemoglobin complex Biological process • transport • positive regulation of cell death • oxygen transport • response to hydrogen peroxide • hydrogen peroxide catabolic process • protein heterooligomerization Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	3040	15122
Ensembl	ENSG00000188536	ENSMUSG00000069919
UniProt	P69905	P01942
RefSeq (mRNA)	NM_000517	NM_008218.2
RefSeq (protein)	NP_000508	NP_032244.2
Location (UCSC)	Chr 16: 0.16 – 0.16 Mb	Chr 11: 32.18 – 32.18 Mb
PubMed search	[1]	[2]

Hemoglobin, alpha 2 also known as HBA2 is a gene that in humans codes for the alpha globin chain of hemoglobin.

Function

The human alpha globin gene cluster located on chromosome 16 spans about 30 kb and includes seven alpha like globin genes and pseudogenes: 5'- HBZ - HBZP1 - HBM - HBAP1 - HBA2 - HBA1 - HBQ1 -3'. The HBA2 (α₂) and HBA1 (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. Two α-chains plus two-β chains constitute HbA, which in normal adult life comprises about 97% of the total hemoglobin; alpha chains combine with delta chains to constitute HbA-2, which with HbF (fetal hemoglobin) makes up the remaining 3% of adult hemoglobin. Alpha thalassemias result from deletions of each of the alpha genes as well as deletions of both HBA2 and HBA1; some nondeletion alpha thalassemias have also been reported.

Further reading

• Richter F, Meurers BH, Zhu C, et al. (2009). "Neurons Express Hemoglobin α- and β-Chains in Rat and Human Brains". J. Comp. Neurol. 515 (5): 538–47. doi:10.1002/cne.22062. PMC 3123135. PMID 19479992. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3123135. 
• Phylipsen M, Vogelaar IP, Schaap RA, et al. (2010). "A new alpha(0)-thalassemia deletion found in a Dutch family (--(AW))". Blood Cells Mol. Dis. 45 (2): 133–5. doi:10.1016/j.bcmd.2010.05.004. PMID 20682466. 
• Sessa R, Puzone S, Ammirabile M, et al. (2010). "Identification and molecular characterization of the --CAMPANIA deletion, a novel alpha (0) -thalassemic defect, in two unrelated Italian families [corrected]". Am. J. Hematol. 85 (2): 143–4. doi:10.1002/ajh.21591. PMID 20054848. 
• Yin XL, Zhang XH, Zhou TH, et al. (2010). "Hemoglobin H disease in Guangxi province, Southern China: clinical review of 357 patients". Acta Haematol. 124 (2): 86–91. doi:10.1159/000314058. PMID 20639625. 
• Joly P, Lacan P, Bererd M, et al. (2009). "Description of two new alpha variants: Hb Canuts [alpha85(F6)Asp-->His (alpha1)] and Hb Ambroise Pare [alpha117(GH5)Phe-->Ile (alpha2)]; two new beta variants: Hb Beaujolais [beta84(EF8)Thr-->Asn] and Hb Monplaisir [beta147 (Tyr-Lys-Leu-Ala-Phe-Phe-Leu-Leu-Ser-Asn-Phe-Tyr-158-COOH)] and one new delta variant: Hb (A2)North Africa [delta59(E3)Lys-->Met]". Hemoglobin 33 (3): 196–205. doi:10.1080/03630260903058685. PMID 19657833. 
• Harteveld CL, Oosterhuis WP, Schoenmakers CH, et al. (2010). "alpha-thalassaemia masked by beta gene defects and a new polyadenylation site mutation on the alpha2-globin gene". Eur. J. Haematol. 84 (4): 354–8. doi:10.1111/j.1600-0609.2009.01380.x. PMID 19912309. 
• Kapralov A, Vlasova II, Feng W, et al. (2009). "Peroxidase Activity of Hemoglobin·Haptoglobin Complexes: COVALENT AGGREGATION AND OXIDATIVE STRESS IN PLASMA AND MACROPHAGES". J. Biol. Chem. 284 (44): 30395–407. doi:10.1074/jbc.M109.045567. PMC 2781594. PMID 19740759. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2781594. 
• Roy P, Bhattacharya G, Banerjee D, et al. (2009). "Hb Sallanches [alpha104(G11)Cys-->Tyr, TGC>TAC] occurs frequently on the Indian subcontinent". Hemoglobin 33 (6): 486–91. doi:10.3109/03630260903336164. PMID 19958194. 
• Giardina B, Messana I, Scatena R, Castagnola M (1995). "The multiple functions of hemoglobin". Crit. Rev. Biochem. Mol. Biol. 30 (3): 165–96. doi:10.3109/10409239509085142. PMID 7555018. 
• Higgs DR, Vickers MA, Wilkie AO, et al. (1989). "A review of the molecular genetics of the human alpha-globin gene cluster". Blood 73 (5): 1081–104. PMID 2649166. 
• Ribeiro DM, Sonati MF (2008). "Regulation of human alpha-globin gene expression and alpha-thalassemia". Genet. Mol. Res. 7 (4): 1045–53. doi:10.4238/vol7-4gmr472. PMID 19048483. 
• Waye JS, Eng B, Dutly F, Frischknecht H (2009). "alpha-Thalassemia caused by two novel splice mutations of the alpha2-globin gene: IVS-I-1 (G>A and G>T)". Hemoglobin 33 (6): 519–22. doi:10.3109/03630260903333377. PMID 19958200. 
• Coelho A, Picanço I, Seuanes F, et al. (2010). "Novel large deletions in the human alpha-globin gene cluster: Clarifying the HS-40 long-range regulatory role in the native chromosome environment". Blood Cells Mol. Dis. 45 (2): 147–53. doi:10.1016/j.bcmd.2010.05.010. PMID 20580289. 
• Sharma V, Kumar B, Kumar G, Saxena R (2009). "Alpha globin gene numbers: an important modifier of HbE/beta thalassemia". Hematology 14 (5): 297–300. doi:10.1179/102453309X446126. PMID 19843387. 
• Turbpaiboon C, Wilairat P (2010). "Alpha-hemoglobin stabilizing protein: molecular function and clinical correlation". Front. Biosci. 15: 1–11. doi:10.2741/3601. PMID 20036801. 
• Voon HP, Vadolas J (2008). "Controlling alpha-globin: a review of alpha-globin expression and its impact on beta-thalassemia". Haematologica 93 (12): 1868–76. doi:10.3324/haematol.13490. PMID 18768527. 
• Giordano PC, Cnossen MH, Joosten AM, et al. (2010). "Codon 24 (TAT>TAG) and codon 32 (ATG>AGG) (Hb Rotterdam): two novel alpha2 gene mutations associated with mild alpha-thalassemia found in the same family after newborn screening". Hemoglobin 34 (4): 354–65. doi:10.3109/03630269.2010.486341. PMID 20642333. 
• Mahdavi MR, Kowsarian M, Karami H, et al. (2010). "Prevalence of hemoglobin alpha-chain gene deletion in neonates in North of Iran". Eur Rev Med Pharmacol Sci 14 (10): 871–5. PMID 21222374. 
• Balakrishnan G, Zhao X, Podstawska E, et al. (2009). "Subunit-Selective Interrogation of CO Recombination in Carbonmonoxy Hemoglobin by Isotope-Edited Time-resolved Resonance Raman Spectroscopy". Biochemistry 48 (14): 3120–6. doi:10.1021/bi802190f. PMC 2722936. PMID 19245215. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2722936. 
• Zhu C, Yu W, Xie J, et al. (2010). "Hemoglobin H disease due to a de novo mutation at the α2-globin gene and an inherited common α-thalassemia deletion found in a Chinese boy". Blood Cells Mol. Dis. 45 (3): 223–6. doi:10.1016/j.bcmd.2010.07.005. PMID 20691621. 

External Links

• GeneReviews/NCBI/NIH/UW entry on Alpha-Thalassemia
• OMIM etries on Alpha-Thalassemia

This article incorporates text from the United States National Library of Medicine, which is in the public domain.