PMID- 1315769
OWN - NLM
STAT- MEDLINE
DCOM- 19920609
LR  - 20210210
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 267
IP  - 14
DP  - 1992 May 15
TI  - Infrared evidence of azide binding to iron, copper, and non-metal sites in heart 
      cytochrome c oxidase.
PG  - 9757-66
AB  - Interactions of azide ion with bovine heart cytochrome c oxidase (CcO) at five 
      redox levels (IV) to (0), obtained by zero to four electron reduction of fully 
      oxidized enzyme CcO(IV), were monitored by infrared and visible/Soret spectra. 
      Partially reduced CcO gave three azide asymmetric stretch band at 2040, 2016, and 
      2004 cm-1 for CcO(III)N3 and two at 2040 and 2016 cm-1 for CcO(II)N3 and 
      CcO(I)N3. Resting CcO(IV) reacts with N3- to give one band at 2041 cm-1 assigned 
      to CuB2+N3 and another at 2051 cm-1 to N3- that is associated with protein but is 
      not bound to a metal ion. At high azide concentrations the weak association of 
      many azide molecules with non-metal protein sites was observed at all redox 
      levels. These findings provide direct evidence for 1) N3- binding to CuB as well 
      as Fea3 in partially reduced enzyme, but no binding to Fea3 in fully oxidized 
      enzyme and no binding to either metal in fully reduced enzyme; 2) a long range 
      effect of the oxidation state of Fea or CuA on ligand binding at heme a3, but not 
      at CuB; and 3) an insensitivity of either Fea3 or CuB ligand site to changes in 
      ligand or oxidation state at the other site. The observed independence of the 
      Fea3 and CuB sites provides further support for Fea3(3)+ OOH, rather than 
      Fea3(3)+ OOCuB2+, as an intermediate in the reduction of O2 to water by the 
      oxidase.
FAU - Yoshikawa, S
AU  - Yoshikawa S
AD  - Department of Biochemistry, Colorado State University, Fort Collins 80523.
FAU - Caughey, W S
AU  - Caughey WS
LA  - eng
GR  - HL-15980/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Azides)
RN  - 789U1901C5 (Copper)
RN  - E1UOL152H7 (Iron)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Animals
MH  - Azides/*metabolism
MH  - Binding Sites
MH  - Cattle
MH  - Copper/*metabolism
MH  - Electron Transport Complex IV/*metabolism
MH  - Iron/*metabolism
MH  - *Models, Theoretical
MH  - Myocardium/enzymology
MH  - Oxidation-Reduction
MH  - Protein Conformation
MH  - Spectrophotometry
MH  - Spectrophotometry, Infrared
EDAT- 1992/05/15 00:00
MHDA- 1992/05/15 00:01
CRDT- 1992/05/15 00:00
PHST- 1992/05/15 00:00 [pubmed]
PHST- 1992/05/15 00:01 [medline]
PHST- 1992/05/15 00:00 [entrez]
AID - S0021-9258(19)50157-0 [pii]
PST - ppublish
SO  - J Biol Chem. 1992 May 15;267(14):9757-66.