Hemoglobin subunit zeta (HBZ)
The protein contains 142 amino acids for an estimated molecular weight of 15637 Da.
The zeta chain is an alpha-type chain of mammalian embryonic hemoglobin. (updated: Feb. 4, 2015)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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Biological Process
Cellular oxidant detoxification
Erythrocyte maturation
Hydrogen peroxide catabolic process
Negative regulation of transcription by RNA polymerase II
Protein heterooligomerization
Molecular Function
Heme binding
Iron ion binding
Organic acid binding
Oxygen binding
Oxygen carrier activity
The reference OMIM entry for this protein is 142310
Hemoglobin--zeta locus; hbz
Hemoglobin zeta
5-prime @zeta locus
Hemoglobin zeta-2, formerly; hbz2, formerly
Zeta is an early embryonic chain which is substituted for the alpha chain in Hb Portland-1. This unique hemoglobin was found in a newborn infant with multiple congenital anomalies and complex autosomal chromosomal mosaicism (Capp et al., 1967). Its composition was found to be gamma(2) X(2). It was originally thought that the X-chain might be the epsilon chain whose synthesis persisted until after birth because of the chromosomal anomaly; later work indicated that the X-chain is indeed different from epsilon and therefore it is now called zeta. Hb Portland-2 is the designation for zeta(2)-beta(2) found in stillborn infants with homozygous alpha-thalassemia (Randhawa et al., 1984). Melderis et al. (1974) presented evidence for the zeta chain being homologous with the alpha chain. The zeta chains of mice, rabbits and man showed close similarities to each other and significant similarities to the alpha chains of these species. Kamuzora and Lehmann (1975) gave sequence data on the human zeta chain and pointed out a close homology to the alpha chain. Recombinant DNA experiments at Cambridge University provided suggestions that the zeta locus may be linked to the alpha loci (Housman, 1979). Pressley et al. (1980) presented the findings in 2 infants with hemoglobin Bart's hydrops fetalis syndrome (homozygous alpha-thalassemia-1) as evidence that the 5-prime zeta locus is functional. One of the infants had lost the 3-prime-zeta-1 gene but had zeta-globin in the cord blood. In the mouse, Whitney and Russell (1980) concluded that the embryonic alpha-like gene is closely linked to the gene of adult alpha-globin. In mouse embryos heterozygous for alpha-thalassemia, they found no decrease in the proportion of hemoglobins containing the alpha chain as compared to the hemoglobin containing the alpha-like embryonic globin chain. Aschauer et al. (1981) found 57 amino acid differences between the zeta chain and the alpha chain. This finding indicates 'a greater phylogenetic distance' between alpha-type chains than between the beta-type chains. Several of the zeta chain replacements are at positions of structural and functional significance, particularly in relation to the Bohr effect and high oxygen affinity which characterize embryonic hemoglobins (Clegg and Gagnon, 1981). The gene order in the HBAC (hemoglobin alpha cluster) is zeta--11.5 kb--pseudozeta--pseudoalpha--alpha-2--alpha-1. What was formerly called zeta-2, the locus at the 5-prime end of the alpha-globin cluster, is the functional gene. Chung et al. (1984) concluded that deletion of 2 alpha-globin genes on the same chromosome as in alpha-thalassemia is accompanied by the continued expression of embryonic zeta-globin genes in adults. The 3-prime zeta-1 gene, a pseudogene, is highly homologous to the functional 5-prime zeta-2 gene. By genomic mapping and oligonucleotide analysis, Hill et al. (1985) found chromosomes with a zeta-2--zeta-1 rather than a zeta-2--psi-zeta-1 arrangement. Gene conversion of the psi-zeta-1 by the psi-zeta-2 gene appears to have happened. In this interchromosomal process the only identifiable inactivating mutation in the psi-zeta-1 gene was removed. The zeta-2--zeta-1 arrangement was common in all 8 populations studied representing a 'new' type of polymorphism. Stable mRNA transcripts from the converted gene were absent at 16 to 20 weeks of gestation when transcripts from the zeta-2 gene were readily detectable. Zeta-1 (HBZP), or pseudozeta, is very similar to zeta-2 b ... More on the omim web site
May 12, 2019: Protein entry updated
Automatic update: model status changed
Nov. 17, 2018: Protein entry updated
Automatic update: model status changed
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
Oct. 27, 2017: Protein entry updated
Automatic update: model status changed
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 142310 was added.
Feb. 25, 2016: Protein entry updated
Automatic update: model status changed