Cysteine ligand

Fig. 19 Schematic drawing of the structures of the bifunctional ligand cysteine-distamycin and of the corresponding nitrido Tc-99m heterocomplexes...

C/N in higher plants is 7-30 for the entire plant but 20-50 for photosynthetic organs, N/P uses to be 50-80 and C/S about 500 (stoichiometric ratios each). Both S and Se are partly bound into ligands (cysteine, methionine, selenocysteine, dimethyl selenide and many plant components such as those of Allium species including garlic), but likewise partly in weakly complexing anions like SO/ or SeO ", respectively (total S in leaves or needles is about 3 mg/g DM or 90 mmol/kg C/S 450 and N/S < 20). 

Fig. 3. Push-pull mechanism for the heterolysis of the 0-0 bond of an iron-peroxo complex. The oval indicates an electron-rich ligand, such as a porphyrin L is a heme-proximal ligand (cysteine or histidine).

S-Donor ligands. Cysteine complexes of formula [PML2] (M = Pd or Pt) have been prepared by treating K2[MCl4] with excess cysteine hydrochloride. Their i.r. spectra confirm co-ordination ina S and O sites, with free amine groups. Similarly the P-ketosulphoxide complex [PdL2] (L = PhCOCH2SOMe) has been shown to have the structure (54 M = Pd). ° In an extension of previous... 

Fig. 6.30 P450 protein/partner complexes. A cartoon view is shown for two crystal structures documenting distinct P450 protein/partner protein interactions. Panel A depicts the P450cam (CYPIOIAI )-putidaredoxin (PD) complex with the redox partner depicted in orange (PDB 4JWS). The 2Fe-2S cluster is in close vicinity of the heme, with the PD docking on the proximal face of the P450 near to the fifth ligand cysteinate-iron bond region [770]. In contrast, panel B shows the interaction observed...

Figure 11 The 3D NMR structure of the two domains in blue crab MTl. The Cd irais are numbered according to their resonance position from low field to high field along with the sequence number of the liganding cysteines (PDB entries IDMC and IDME).

---