Biology Reference
In-Depth Information
any evidence that they are functional, they would be rich in structural,
chemical and evolutionary clues.
In view of possible signalling roles, further covalent modifications, as
observed in mammalian proteins (
Ascenzi et al., 2013
), should be considered
as well. Tyrosine nitration, phosphorylation, carbamation, glycosylation,
etc., may all play a role in globins.
6.3. Concluding remarks
The diversity of globins throughout all kingdoms of life strongly suggests
that these proteins perform fundamentally necessary roles within cells, yet
especially in photosynthetic microbes, we are only beginning to define what
those roles might be. The great need in this field is to formulate an under-
standing of the native function of globins in photosynthetic microbes.
Growing reservoirs of genetic information have provided us with a great
opportunity by revealing multiple globin genes within model photosyn-
thetic organisms. These organisms, such as
Synechococcus
sp. PCC 7002
and
C. reinhardtii
, have been extensively used for physiological characteriza-
tion, and many analytical techniques are already established for the
in vivo
characterization of proteins. By identifying orthologous proteins in model
organisms and enhancing our structural information about their character-
istics, we can finally begin to address the root questions asked throughout
this chapter. From phylogenetic studies, we know that these proteins are
important. From structural and recombinant studies, we understand what
potential activity they exhibit. We must now focus on what functions they
perform and how they enhance the survival of both cyanobacteria and algae
throughout the diverse environments in which they exist.
REFERENCES
