A model of the nodulin 26 channel protein has been constructed based on
comparative modeling and molecular dynamics simulations. Structural features of
the protein indicate a selectivity filter that differs from those of the known
structures of Escherichia coli glycerol facilitator and mammalian aquaporin 1.
The model structure also reveals important roles of Ser207 and Phe96 in ligand
binding and transport.
Figure 4.
Fig. 4. a: Interaction of second formamide molecule (CP2)
with Ser207 when the first one (CP1) reaches at the constriction
region. b: Two rotamer conformations, indicated by side chain
torsion angle χ value of Ser207 during the 120 ps trajectory
for four monomers A, B, C and D. Ser207 in monomers A and D
changes their side chain conformation in the trajectory. χ[1]
value near zero corresponds to the conformation of Ser207 when
it interacts to ligand molecule at the region in between the
selectivity filter and the constriction region.
Figure 5.
Fig. 5. Comparison of electrostatic potential surfaces of
nodulin 26, GlpF and AQP1 at the extracellular face. The figure
was generated by GRASP [30].
The above figures are
reprinted
by permission from the Federation of European Biochemical Societies:
FEBS Lett
(2004,
558,
39-44)
copyright 2004.
