PMID- 7873550
OWN - NLM
STAT- MEDLINE
DCOM- 19950404
LR  - 20190613
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 34
IP  - 8
DP  - 1995 Feb 28
TI  - 8-Azido-ATP modification of cytochrome c: retardation of its electron-transfer 
      activity to cytochrome c oxidase.
PG  - 2678-85
AB  - Horse heart cytochrome c has been modified by 8-azido-ATP and the 
      electron-transfer activity of the modified cytochrome c's to bovine heart 
      cytochrome c oxidase (CcO) under physiological ionic strengths has been studied 
      by the laser flash photolysis technique with 5-deazariboflavin and EDTA as the 
      electron donor. The intermolecular electron transfer between the redox protein 
      partners was shown to be extremely slow. The 8-azido-ATP-modified system 
      exhibited less than 5% of the intracomplex electron-transfer rate observed 
      between native cytochrome c and CcO under otherwise identical conditions. The 
      binding affinity of the modified cytochrome c was greatly reduced (3 orders of 
      magnitude) at low ionic strengths; however, it was only slightly reduced (by a 
      factor of 2) relative to the native protein at physiological ionic strengths. 
      Thus, the binding affinity of the ATP-cytochrome c adducts is relatively 
      insensitive to the ionic strength compared to the native enzyme, suggesting that 
      a different docking conformation is assumed by the ATP-cytochrome c adducts in 
      their interaction with the oxidase. Since the redox potential of the modified 
      cytochrome c is close to the value of its native form, we conclude that there has 
      been a change in the docking of the cytochrome c to CcO and the electronic 
      coupling between heme c and CuA upon 8-azido-ATP modification.
FAU - Lin, J
AU  - Lin J
AD  - A.A. Noyes Laboratory of Chemical Physics, California Institute of Technology, 
      Pasadena 91125.
FAU - Wu, S
AU  - Wu S
FAU - Lau, W T
AU  - Lau WT
FAU - Chan, S I
AU  - Chan SI
LA  - eng
GR  - GM 22432/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Azides)
RN  - 0 (Cytochrome c Group)
RN  - 53696-59-6 (8-azidoadenosine 5'-triphosphate)
RN  - 8L70Q75FXE (Adenosine Triphosphate)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Adenosine Triphosphate/*analogs & derivatives/chemistry
MH  - Animals
MH  - Azides/*chemistry
MH  - Cattle
MH  - Cytochrome c Group/*chemistry/*metabolism
MH  - Electron Transport
MH  - Electron Transport Complex IV/*metabolism
MH  - Horses
MH  - In Vitro Techniques
MH  - Kinetics
MH  - Myocardium/metabolism
MH  - Oxidation-Reduction
MH  - Photolysis
EDAT- 1995/02/28 00:00
MHDA- 1995/02/28 00:01
CRDT- 1995/02/28 00:00
PHST- 1995/02/28 00:00 [pubmed]
PHST- 1995/02/28 00:01 [medline]
PHST- 1995/02/28 00:00 [entrez]
AID - 10.1021/bi00008a035 [doi]
PST - ppublish
SO  - Biochemistry. 1995 Feb 28;34(8):2678-85. doi: 10.1021/bi00008a035.