TY - JOUR
T1 - Functional diversification of sea lamprey globins in evolution and development
AU - Fago, Angela
AU - Rohlfing, Kim
AU - Petersen, Elin E.
AU - Jendroszek, Agnieszka
AU - Burmester, Thorsten
PY - 2018/2
Y1 - 2018/2
N2 - 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 O
2 transport and muscle-based O
2 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 O
2 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 O
2 affinity and nitrite reductase activity, while the two hemoglobins display low O
2 affinity and nitrite reductase activity. Cygb and aHb6 but not aHb5a show cooperative O
2 binding, correlating with increased stability of dimers, as shown by gel filtration and molecular modeling. The high O
2-affinity and the lack of cooperativity confirm the identity of the sea lamprey aMb1 as O
2 storage protein of the muscle. The dimeric structure and O
2-binding properties of sea lamprey and mammalian Cygb were very similar, suggesting a conservation of function since their divergence around 500 million years ago.
AB - 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 O
2 transport and muscle-based O
2 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 O
2 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 O
2 affinity and nitrite reductase activity, while the two hemoglobins display low O
2 affinity and nitrite reductase activity. Cygb and aHb6 but not aHb5a show cooperative O
2 binding, correlating with increased stability of dimers, as shown by gel filtration and molecular modeling. The high O
2-affinity and the lack of cooperativity confirm the identity of the sea lamprey aMb1 as O
2 storage protein of the muscle. The dimeric structure and O
2-binding properties of sea lamprey and mammalian Cygb were very similar, suggesting a conservation of function since their divergence around 500 million years ago.
KW - Hemoglobin
KW - Myoglobin
KW - Cytoglobin
KW - Adaptation
KW - Oxygen
KW - Evolution
KW - NITRITE REDUCTASE-ACTIVITY
KW - PETROMYZON-MARINUS
KW - OXYGEN-AFFINITY
KW - CRYSTAL-STRUCTURE
KW - STRUCTURAL BASIS
KW - ALLOSTERIC REGULATION
KW - CONVERGENT EVOLUTION
KW - JAWLESS VERTEBRATES
KW - HEMOGLOBIN-FUNCTION
KW - LIGAND-BINDING
UR - http://www.scopus.com/inward/record.url?scp=85034858189&partnerID=8YFLogxK
U2 - 10.1016/j.bbapap.2017.11.009
DO - 10.1016/j.bbapap.2017.11.009
M3 - Journal article
C2 - 29155105
SN - 1570-9639
VL - 1866
SP - 283
EP - 291
JO - B B A - Proteins and Proteomics
JF - B B A - Proteins and Proteomics
IS - 2
ER -