5ycj | pdb_00005ycj
From Proteopedia
Ancestral myoglobin aMbWb' of Basilosaurus relative (polyphyly) imidazole-ligand
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Structural highlights
FunctionMYG_BALMY Monomeric heme protein which primary function is to store oxygen and facilitate its diffusion within muscle tissues. Reversibly binds oxygen through a pentacoordinated heme iron and enables its timely and efficient release as needed during periods of heightened demand. Depending on the oxidative conditions of tissues and cells, and in addition to its ability to bind oxygen, it also has a nitrite reductase activity whereby it regulates the production of bioactive nitric oxide. Under stress conditions, like hypoxia and anoxia, it also protects cells against reactive oxygen species thanks to its pseudoperoxidase activity.[UniProtKB:P02144] Publication Abstract from PubMedExtant cetaceans, such as sperm whale, acquired the great ability to dive into the ocean depths during the evolution from their terrestrial ancestor that lived about 50 million years ago. Myoglobin (Mb) is highly concentrated in the myocytes of diving animals, in comparison with those of land animals, and is thought to play a crucial role in their adaptation as the molecular aqualung. Here, we resurrected ancestral whale Mbs, which are from the common ancestor between toothed and baleen whales (Basilosaurus), and from a further common quadrupedal ancestor between whale and hippopotamus (Pakicetus). The experimental and theoretical analyses demonstrated that whale Mb adopted two distinguished strategies to increase the protein concentration in vivo along the evolutionary history of deep sea adaptation; gaining precipitant tolerance in the early phase of the evolution, and increase of folding stability in the late phase. Tracing whale myoglobin evolution by resurrecting ancient proteins.,Isogai Y, Imamura H, Nakae S, Sumi T, Takahashi KI, Nakagawa T, Tsuneshige A, Shirai T Sci Rep. 2018 Nov 15;8(1):16883. doi: 10.1038/s41598-018-34984-6. PMID:30442991[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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