Hemoglobinand Myoglobin Functions
Hemoglobinand Myoglobin Functions
Hemoglobinand Myoglobin are globular proteins mainly used to transport oxygento the body cells. Gene duplication is an essential topic thatrelates to the functionality of two globular proteins (Jonathan,2012).The major difference that exist between hemoglobin andmyoglobin is traced back to gene replication. Gene duplication, alsoknown as chromosomal duplication, refers to the replication of aregion of DNA that comprise of the gene. The common sources of genereplication include aneuploidy, retro-transportation event,replication slippage, ectopic homologous recombination. Variousresearchers have argued that genome duplication is responsible fordiversity and complexity (Crow & Wagner, 2005). In the past fewdecades, gene duplication has been considered as the major factorcontributing to the evolution of eukaryotes. Notably, geneduplication is both an ancient and a continuing process in plants,yeast, and animals. Despite the fact that the two globular proteinstransport oxygen in the body, gene replication is responsible for thedifferences in the way the two perform this function.
Researchersfrom different studies argue that regardless of how the first genewas generated, gene replication is the major cause of evolution. Forinstance, gene duplication adds extra materials to the genome in anabnormal separation of chromosomes through meiosis or mitosis.Secondly, erroneous DNA duplication can add extra materials to thegenome. Various mechanisms of gene duplication affect the primaryfunction of hemoglobin in the body (Crow &Wagner, 2005). In1970’s and 1980’s some researchers conducted a study thatinvestigated the diversification of hemoglobin in vertebrates. Inother subsequent studies, it was speculated that the first genes thatevolved as a result of gene replication were known as alpha and betahemoglobin. These two types of hemoglobin were used to transportoxygen in erythrocytes. Therefore, the globin family is one of themost cited examples of advancement by gene replication. Notably, thehemoglobin comprises of two dimers, each one comprising of an alphaglobins and a beta globins. The recent duplication of beta globinshas given rise to gamma, epsilon, and delta genes, while the alphaglobins have replicated to zeta and epsilon globins (Storz, Opaza &,Hoffmann, 2013). It is important to note that hemoglobin is found inthe red blood cells of circulating blood. The hemoglobin must be nthe capacity of off-loading oxygen when there is low level of oxygenin the active tissues.
Quaternarystructure is one the protein structures that refers to spatialinteractions and arrangement of subunits that come together to form amulti-subunit or multimeric proteins. These types of proteins aremade using multiple polypeptide chain. Multimeric hemoglobin compriseof both alpha globins and beta globins. The effectiveness ofhemoglobin as a mode of transporting oxygen in body cells originatesfrom its multimeric quaternary structure. To illustrate, theinteraction between the different subunits facilitates oxygenbidding. Moreover, this cooperation allows fast and efficientunloading of oxygen even in cases of low level of oxygen in theblood. Additionally, hemoglobin collects carbon dioxide from the bodyand takes it back to the lungs. Notably, the heme structure of thehemoglobin has a single central ion that is attached to the fourpyrol rings.
Onthe other hand, Myoglobin is an iron and oxygen bidding proteincommonly found in tissue muscle of vertebrates, particularly mammals.It is closely similar to hemoglobin, a protein found in RBC (redblood cells). It is used to transport oxygen to tissue muscles, whichallows animals to hold breath for some time. Diving mammals likeseals and whales have muscles, which have a high abundance ofmyoglobin. As compare to hemoglobin, myoglobin is a monomer, whichcontains singe units. Moreover, myoglobin is said to work better inhigh affinity for oxygen. Additionally, a myoglobin contains a hemegroup that gives blood and muscles the red color. The organic elementconsists of four pyrrole bands that are connected using methanebridges[ CITATION Jon12 l 1033 ].The oxidation ofiron atoms gives rise to the red color found in the blood andmuscles. Further, the iron atoms are bonded with nitrogen atoms foundin the pyrole rings.
Therefore,myoglobin contains a tertiary structure and it does not have anyquaternary structure. It is important to note that when oxygen leavesthe myoglobin, it becomes a dioxygen instead of superoxide. The majorreason is that superoxide can be harmful to most biologicalprocesses. Unlike hemoglobin, myoglobin is not efficient intransporting oxygen. It other words, it does not show cooperativityof oxygen bidding since it takes up oxygen and release it in severeconditions. Since myoglobin allows storage of oxygen in body muscles,it is significant when the body is in insufficiency of oxygen,especially during anaerobic activities.
Inconclusion, hemoglobin and myoglobin are globular proteins that playan important role in transportation of oxygen in the body. The twoglobular proteins have common characteristics in the way theirfunction. For instance, they work best in high oxygen affinity.Nonetheless, there are also some significant differences in the waytwo globular proteins function. After gene duplication, alpha globinsand beta globins were formed in the hemoglobin. Consequently,multisubunit quaternary structures are formed which increases thecooperativity of oxygen bidding. On the other hand, the single unitstructure of the myoglobin does not allow it to have cooperativity inoxygen bidding.
Crow,K., & Wagner, G. (2005). What Is the role of genome duplicationin the evolution of complexity and diversity? MolecularBiology and Evolution, 887-892.
Storz,J., Opaza, J., & Hoffmann, F. (2013). Gene duplication, genomeduplication, and the functional diversification of vertebrateglobins. MolPhylogenet Evol., 469-478.
Jonathan,M. (2012, October 4). Gene Duplication and the Origin of NovelBiological Information: A Case Study of the Globins. Evolutionnews.Retrieved fromhttp://www.evolutionnews.org/2012/10/gene_duplicatio064971.html