Globin

Cross references:   Heme   Myoglobin   
Red Nucleus     Red Nucleus Evolution    
Extrapyramidal System    Fast vs. Slow Twitch Muscles   


Globin (Wiki)   
    "The globins are a family of globular proteins, which are thought to share a common ancestor. These proteins all incorporate the globin fold, a series of eight alpha helical segments. Two prominent members of this family include myoglobin and hemoglobin, which both bind the heme (also haem) prosthetic group. Both of these proteins are reversible oxygen binders. 

Globin family PDB 1hba EBI.jpg

Globins are haem-containing proteins involved in binding and/or transporting oxygen. They belong to a very large and well studied family that is widely distributed in many organisms.[2]

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A phylogenomic profile of globins   
     Abstract:   
    Full length HTML for free: 
   
From the Abstract
    "
Globins occur in all three kingdoms of life"      
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A census of globins in 26 archaeal, 245 bacterial and 49 eukaryote genomes was carried out. Only approximately 25% of archaea have globins, including globin coupled sensors, related single domain globins and 2-over-2 globins. From one to seven globins per genome were found in approximately 65% of the bacterial genomes: the presence and number of globins are positively correlated with genome size."      
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Over 90% of eukaryotes have globins"  
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Although Bacteria have all three types of globins, Archaeado not have flavohemoglobins and Eukaryotes lack globin coupled sensors. Since the hemoglobins in organisms other than animals are enzymes or sensors, it is likely that the evolution of an oxygen transport function accompanied the emergence of multicellular animals."  
My comment
    This makes it clear that the globins are widely distributed.  However, it doesn't say anything about their color.  How many of them are red?  I read the full length HTML without finding an answer.  However, this may not be important after all.  I've been conflating red muscle fibers with the nerves which innervate them.  There is no reason to believe that the nerves which innervate red muscle fibers are themselves red.   

     













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