Functional diversification of sea lamprey globins in evolution and development

Publication date: February 2018 Source:Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, Volume 1866, Issue 2 Author(s): Angela Fago, Kim Rohlfing, Elin E. Petersen, Agnieszka Jendroszek, Thorsten Burmester Agnathans have a globin repertoire that markedly differs from that of jawed (gnathostome) vertebrates. The sea lamprey (Petromyzon marinus) harbors at least 18 hemoglobin, two myoglobin, two globin X, and one cytoglobin genes. However, agnathan hemoglobins and myoglobins are not orthologous to their cognates in jawed vertebrates. Thus, blood-based O2 transport and muscle-based O2 storage proteins emerged twice in vertebrates from a tissue-globin ancestor. Notably, the sea lamprey displays three switches in hemoglobin expression in its life cycle, analogous to hemoglobin switching in vertebrates. To study the functional changes associated with the evolution and ontogenesis of distinct globin types, we determined O2 binding equilibria, type of quaternary assembly, and nitrite reductase enzymatic activities of one adult (aHb5a) and one embryonic/larval hemoglobin (aHb6), myoglobin (aMb1) and cytoglobin (Cygb) of the sea lamprey. We found clear functional differentiation among globin types expressed at different developmental stages and in different tissues. Cygb and aMb1 have high O2 affinity and nitrite reductase activity, while the two hemoglobins display low O2 affinity and nitrite reductase activity. Cygb and aHb6 but not aHb5a show cooperative O2 bind...

Source: Biochimica et Biophysica Acta (BBA) Proteins and Proteomics - December 16, 2017 Category: Biochemistry Source Type: research