The globins are a superfamily of heme-containing globular proteins, involved in binding and/or transporting oxygen. These proteins all incorporate the globin fold, a series of eight alpha helical segments. Two prominent members include myoglobin and hemoglobin.
What makes the globin genes a gene family?
A set of duplicated genes that encode proteins with similar but nonidentical amino acid sequences is known as a gene family (Lodish et.al., 2000). These hemoglobin proteins have a higher binding affinity for oxygen than the adult hemoglobins encoded by the b and d genes.
How did the globin gene family evolve?
On the basis of this conserved basic structure and its prevalence in living organisms, it has been suggested that globin genes evolved from a common ancestral gene which, after successive duplications and speciation events, led to the genes that encode the widespread globin superfamily [1–5].
Where are globin genes found?
Globin Genes. The globin genes are organized into two clusters (Figure 116-6). The α-like genes are located along a 20-kb distal segment of the short arm of chromosome 16.
How many globin genes are there?
The human β-globin locus is composed of five genes located on a short region of chromosome 11, responsible for the creation of the beta parts (roughly half) of the oxygen transport protein Haemoglobin.
What is the function of globin?
Globin proteins are ubiquitous in living organisms and carry out a variety of functions related to the ability of their prosthetic heme group to bind gaseous ligands such as O2, NO and CO. Moreover, they catalyze important reactions with nitrogen oxide species, such as NO dioxygenation and nitrite reduction.
What is globin made up of?
Globin consists of two linked pairs of polypeptide chains. Hemoglobin S is a variant form of hemoglobin that is present in persons who have sickle cell anemia, a severe hereditary form of anemia in which the cells become crescent-shaped when oxygen is lacking.
What is the globin part of Haemoglobin?
What is the role of globin in human erythrocytes?
Globin, the protein portion of hemoglobin, is broken down into amino acids, which can be sent back to the bone marrow to be used in the production of new erythrocytes. Hemoglobin that is not phagocytized is broken down in the circulation, releasing alpha and beta chains that are removed from circulation by the kidneys.
What is the meaning of globin?
Definition of globin : a colorless protein obtained by removal of heme from a conjugated protein and especially hemoglobin.
How many functional genes are there in the globin cluster?
The cluster contains three functional genes (α 1, α 2, and ζ 2 ), three pseudogenes (evolutionary remnants of genes that are not expressed because of inactivating mutations that prevent production of a functional globin protein), and one gene of undetermined function (a globin-like gene without inactivating mutations).
Is the epsilon-globin gene related to other human beta-like globin genes?
In addition, the evolutionary relationship of the embryonic epsilon-globin gene to the other human beta-like globin genes is defined for the first time. Finally, we describe a model for the involvement of short direct repeat sequences in the generation of deletions in the noncoding and coding regions of beta-like globin genes during evolution.
What are the characteristics of hemoglobin gene regulation?
INSIGHTS INTO GENE REGULATION. Hemoglobin gene expression is restricted to erythroid cells. The genes are expressed at extremely high levels late in erythroid differentiation, with balanced production of α-globin and β-globin. Paralogous globin genes are expressed at progressive developmental stages.
What is the primary structure of human beta-like globin genes?
We present the results of a detailed comparison of the primary structure of human beta-like globin genes and their flanking sequences. Among the sequences located 5′ to these genes are two highly conserved regions which include the sequences ATA and CCAAT located 31 +/- 1 and 77 +/- 10 bp, respectively, 5′ to the mRNA capping site.
