Metalloproteins and Metallopeptides –Natural Metallofoldamers - Metallofoldamers: Supramolecular Architectures from Helicates to Biomimetics - page 15

Figure 1.11 Relaxed-eye stereoviews of (top) the superimposed structures of the activated
“green species” HOO-Co 3þ -deglycopepleomycin (green ball and stick structure; PDB 1AO2)
with a more compact folding than that of the complex upon binding with d(CGTACG) 2 (red
stick structure retrieved from PDB 1AO1) and (middle) deglycopepleomycin-Co 3þ (OOH)-
(CGTACG) 2 structure obtained from NMR studies (PDB 1AO1). Peroxide is bound to the metal
from the bottom in the structure shown. Bottom: crystal structure of bleomycin-binding pro-
tein from Streptoalloteichus hindustanus complexed with a bleomycin congener of an

extended conformation (PDB 2ZHP).

isotropically shifted [118] 1 H NMR signals has been studied by means of NMR [119,120].
The structural model of Fe 2þ -Blm built by the use of NMR relaxation times as constraints
is similar to those of Co 3þ -Blm complexes. Upon binding to the Shble protein from Strep-
toalloteichus hindustanus , Cu-Blm adopts an extended conformation [121] (Figure 1.11),
as opposed to that upon binding to DNA wherein bending of the bithioazole rings occurs
in order to intercalate into the base pairs. Taken together, metallo-Blm represents a proto-
typical natural metallofoldamer which undergoes conformational change upon metal
binding and binding with nucleic acid targets.

1.3.1.2 Bc and Cell Wall Biosynthesis

Bc is a metal-dependent peptidyl antibiotic produced by Bacillus subtilis and B. lichen-
iformis , primarily against Gram-positive bacteria via inhibition of cell wall synthesis