Figure 3.
Figure 3. Stereo C traces
depicting the crystal structures of a, the wild type intertwined
dimer, with the enclosed hydrophilic interface, and b, in a
similar orientation, the 46
47
deletion mutant intertwined dimer in the P4[3] crystal form
(forms I and II). The hydrophilic interface is now in an
'exposed' conformation. When crystallized under high-salt
conditions (crystal form III) c, this same structure is also
observed, but now a tetramer is formed in which a second
intertwined dimer binds with both hydrophilic interfaces
interlocked to form a central, extended -barrel.
The spheres identify the location of equivalent residues
(position 49) central to each polypeptide chain, illustrating
their close proximity in the tetramer and hence the feasibility
of further exchange of polypeptide chains in this region to form
a fully intertwined tetramer.
The above figure is reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Biol
(1998,
5,
778-782)
copyright 1998.
traces
depicting the crystal structures of a, the wild type intertwined
dimer, with the enclosed hydrophilic interface, and b, in a
similar orientation, the 
46
-barrel.
The spheres identify the location of equivalent residues
(position 49) central to each polypeptide chain, illustrating
their close proximity in the tetramer and hence the feasibility
of further exchange of polypeptide chains in this region to form
a fully intertwined tetramer.