PMID- 12470053
OWN - NLM
STAT- MEDLINE
DCOM- 20030515
LR  - 20190814
IS  - 0020-1669 (Print)
IS  - 0020-1669 (Linking)
VI  - 41
IP  - 25
DP  - 2002 Dec 16
TI  - Distal metal effects in cobalt porphyrins related to CcO.
PG  - 6583-96
AB  - Cobalt(II) porphyrins were studied to determine the influence of distal site 
      metalation and superstructure upon dioxygen reactivity in active site models of 
      cytochrome c oxidase (CcO). Monometallic, Co(II)(P) complexes when ligated by an 
      axial imidazole react with dioxygen to form reversible Co-superoxide adducts, 
      which were characterized by EPR and resonance Raman (RR). Unexpectedly, certain 
      Co porphyrins with Cu(I) metalated imidazole pickets do not form mu-peroxo 
      Co(III)/Cu(II) products even though the calculated intermetallic distance 
      suggests this is possible. Instead, cobalt-porphyrin-superoxide complexes are 
      obtained with the distal copper remaining as Cu(I). Moreover, distal metals 
      (Cu(I) or Zn(II)) greatly enhance the stability of the dioxygen adduct, such that 
      Co superoxides of bimetallic complexes demonstrate minimal reversibility. The 
      "trapping" of dioxygen by a second metal is attributed to structural and 
      electrostatic changes within the distal pocket upon metalation. EPR evidence 
      suggests that the terminal oxygen in these bimetallic Co-superoxide systems is 
      H-bonded to the NH of an imidazole picket amide linker, which may contribute to 
      enthalpic stabilization of the dioxygen adduct. Stabilization of the dioxygen 
      adduct in these bimetallic systems suggests one possible role for the distal 
      copper in the Fe/Cu bimetallic active site of terminal oxidases, which form a 
      heme-superoxide/copper(I) adduct upon oxygenation.
FAU - Collman, James P
AU  - Collman JP
AD  - Department of Chemistry, Stanford University, Stanford, California 94305-5080, 
      USA. jpc@stanford.edu
FAU - Berg, Katja E
AU  - Berg KE
FAU - Sunderland, Christopher J
AU  - Sunderland CJ
FAU - Aukauloo, Ally
AU  - Aukauloo A
FAU - Vance, Michael A
AU  - Vance MA
FAU - Solomon, Edward I
AU  - Solomon EI
LA  - eng
GR  - GM 17880-30/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Inorg Chem
JT  - Inorganic chemistry
JID - 0366543
RN  - 0 (Metalloporphyrins)
RN  - 3G0H8C9362 (Cobalt)
RN  - 789U1901C5 (Copper)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Binding Sites
MH  - Catalysis
MH  - Cobalt/*chemistry
MH  - Copper/chemistry
MH  - Electron Spin Resonance Spectroscopy
MH  - Electron Transport Complex IV/*chemistry
MH  - Kinetics
MH  - Metalloporphyrins/*chemical synthesis
MH  - Models, Molecular
MH  - Molecular Conformation
MH  - Molecular Structure
MH  - Oxidation-Reduction
MH  - Oxygen/chemistry
MH  - Spectrum Analysis, Raman
EDAT- 2002/12/10 04:00
MHDA- 2003/05/16 05:00
CRDT- 2002/12/10 04:00
PHST- 2002/12/10 04:00 [pubmed]
PHST- 2003/05/16 05:00 [medline]
PHST- 2002/12/10 04:00 [entrez]
AID - ic020395i [pii]
AID - 10.1021/ic020395i [doi]
PST - ppublish
SO  - Inorg Chem. 2002 Dec 16;41(25):6583-96. doi: 10.1021/ic020395i.