| Structural highlights
1j7w is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: |
| | Related: | 1qi8, 1j7s, 1j7y |
| Gene: | HBA HUMAN (Homo sapiens), HBB HUMAN (Homo sapiens) |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Disease
[HBB_HUMAN] Defects in HBB may be a cause of Heinz body anemias (HEIBAN) [MIM:140700]. This is a form of non-spherocytic hemolytic anemia of Dacie type 1. After splenectomy, which has little benefit, basophilic inclusions called Heinz bodies are demonstrable in the erythrocytes. Before splenectomy, diffuse or punctate basophilia may be evident. Most of these cases are probably instances of hemoglobinopathy. The hemoglobin demonstrates heat lability. Heinz bodies are observed also with the Ivemark syndrome (asplenia with cardiovascular anomalies) and with glutathione peroxidase deficiency.[1] [2] [3] [4] Defects in HBB are the cause of beta-thalassemia (B-THAL) [MIM:613985]. A form of thalassemia. Thalassemias are common monogenic diseases occurring mostly in Mediterranean and Southeast Asian populations. The hallmark of beta-thalassemia is an imbalance in globin-chain production in the adult HbA molecule. Absence of beta chain causes beta(0)-thalassemia, while reduced amounts of detectable beta globin causes beta(+)-thalassemia. In the severe forms of beta-thalassemia, the excess alpha globin chains accumulate in the developing erythroid precursors in the marrow. Their deposition leads to a vast increase in erythroid apoptosis that in turn causes ineffective erythropoiesis and severe microcytic hypochromic anemia. Clinically, beta-thalassemia is divided into thalassemia major which is transfusion dependent, thalassemia intermedia (of intermediate severity), and thalassemia minor that is asymptomatic.[5] Defects in HBB are the cause of sickle cell anemia (SKCA) [MIM:603903]; also known as sickle cell disease. Sickle cell anemia is characterized by abnormally shaped red cells resulting in chronic anemia and periodic episodes of pain, serious infections and damage to vital organs. Normal red blood cells are round and flexible and flow easily through blood vessels, but in sickle cell anemia, the abnormal hemoglobin (called Hb S) causes red blood cells to become stiff. They are C-shaped and resembles a sickle. These stiffer red blood cells can led to microvascular occlusion thus cutting off the blood supply to nearby tissues. Defects in HBB are the cause of beta-thalassemia dominant inclusion body type (B-THALIB) [MIM:603902]. An autosomal dominant form of beta thalassemia characterized by moderate anemia, lifelong jaundice, cholelithiasis and splenomegaly, marked morphologic changes in the red cells, erythroid hyperplasia of the bone marrow with increased numbers of multinucleate red cell precursors, and the presence of large inclusion bodies in the normoblasts, both in the marrow and in the peripheral blood after splenectomy.[6]
Function
[HBB_HUMAN] Involved in oxygen transport from the lung to the various peripheral tissues.[7] LVV-hemorphin-7 potentiates the activity of bradykinin, causing a decrease in blood pressure.[8]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The effect of mutagenesis on O(2), CO, and NO binding to mutants of human hemoglobin, designed to modify some features of the reactivity that hinder use of hemoglobin solutions as blood substitute, has been extensively investigated. The kinetics may be interpreted in the framework of the Monod-Wyman-Changeux two-state allosteric model, based on the high-resolution crystallographic structures of the mutants and taking into account the control of heme reactivity by the distal side mutations. The mutations involve residues at topological position B10 and E7, i.e., Leu (B10) to Tyr and His (E7) to Gln, on either the alpha chains alone (yielding the hybrid tetramer Hbalpha(YQ)), the beta chains alone (hybrid tetramer Hbbeta(YQ)), or both types of chains (Hb(YQ)). Our data indicate that the two mutations affect ligand diffusion into the pocket, leading to proteins with low affinity for O(2) and CO, and especially with reduced reactivity toward NO, a difficult goal to achieve. The observed kinetic heterogeneity between the alpha(YQ) and beta(YQ) chains in Hb(YQ) has been rationalized on the basis of the three-dimensional structure of the active site. Furthermore, we report for the first time an experiment of partial CO binding, selective for the beta chains, to high salt crystals of the mutant Hb(YQ) in the T-state; these crystallographic data may be interpreted as "snapshots" of the initial events possibly occurring on ligand binding to the T-allosteric state of this peculiar mutant Hb.
Control of heme reactivity by diffusion: structural basis and functional characterization in hemoglobin mutants.,Miele AE, Draghi F, Arcovito A, Bellelli A, Brunori M, Travaglini-Allocatelli C, Vallone B Biochemistry. 2001 Dec 4;40(48):14449-58. PMID:11724557[9]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Thillet J, Cohen-Solal M, Seligmann M, Rosa J. Functional and physicochemical studies of hemoglobin St. Louis beta 28 (B10) Leu replaced by Gln: a variant with ferric beta heme iron. J Clin Invest. 1976 Nov;58(5):1098-1106. PMID:186485 doi:http://dx.doi.org/10.1172/JCI108561
- ↑ Rahbar S, Feagler RJ, Beutler E. Hemoglobin Hammersmith (beta 42 (CD1) Phe replaced by Ser) associated with severe hemolytic anemia. Hemoglobin. 1981;5(1):97-105. PMID:6259091
- ↑ Blouquit Y, Bardakdjian J, Lena-Russo D, Arous N, Perrimond H, Orsini A, Rosa J, Galacteros F. Hb Bruxelles: alpha 2A beta (2)41 or 42(C7 or CD1)Phe deleted. Hemoglobin. 1989;13(5):465-74. PMID:2599881
- ↑ Rees DC, Rochette J, Schofield C, Green B, Morris M, Parker NE, Sasaki H, Tanaka A, Ohba Y, Clegg JB. A novel silent posttranslational mechanism converts methionine to aspartate in hemoglobin Bristol (beta 67[E11] Val-Met->Asp). Blood. 1996 Jul 1;88(1):341-8. PMID:8704193
- ↑ Thein SL, Hesketh C, Taylor P, Temperley IJ, Hutchinson RM, Old JM, Wood WG, Clegg JB, Weatherall DJ. Molecular basis for dominantly inherited inclusion body beta-thalassemia. Proc Natl Acad Sci U S A. 1990 May;87(10):3924-8. PMID:1971109
- ↑ Thein SL, Hesketh C, Taylor P, Temperley IJ, Hutchinson RM, Old JM, Wood WG, Clegg JB, Weatherall DJ. Molecular basis for dominantly inherited inclusion body beta-thalassemia. Proc Natl Acad Sci U S A. 1990 May;87(10):3924-8. PMID:1971109
- ↑ Ianzer D, Konno K, Xavier CH, Stocklin R, Santos RA, de Camargo AC, Pimenta DC. Hemorphin and hemorphin-like peptides isolated from dog pancreas and sheep brain are able to potentiate bradykinin activity in vivo. Peptides. 2006 Nov;27(11):2957-66. Epub 2006 Aug 9. PMID:16904236 doi:S0196-9781(06)00309-3
- ↑ Ianzer D, Konno K, Xavier CH, Stocklin R, Santos RA, de Camargo AC, Pimenta DC. Hemorphin and hemorphin-like peptides isolated from dog pancreas and sheep brain are able to potentiate bradykinin activity in vivo. Peptides. 2006 Nov;27(11):2957-66. Epub 2006 Aug 9. PMID:16904236 doi:S0196-9781(06)00309-3
- ↑ Miele AE, Draghi F, Arcovito A, Bellelli A, Brunori M, Travaglini-Allocatelli C, Vallone B. Control of heme reactivity by diffusion: structural basis and functional characterization in hemoglobin mutants. Biochemistry. 2001 Dec 4;40(48):14449-58. PMID:11724557
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