PMID- 11841222
OWN - NLM
STAT- MEDLINE
DCOM- 20020327
LR  - 20190613
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 41
IP  - 7
DP  - 2002 Feb 19
TI  - Mutants of the CuA site in cytochrome c oxidase of Rhodobacter sphaeroides: II. 
      Rapid kinetic analysis of electron transfer.
PG  - 2298-304
AB  - The function of the binuclear Cu(A) center in cytochrome c oxidase (CcO) was 
      studied using two Rhodobacter sphaeroides CcO mutants involving direct ligands of 
      the Cu(A) center, H260N and M263L. The rapid electron-transfer kinetics of the 
      mutants were studied by flash photolysis of a cytochrome c derivative labeled 
      with ruthenium trisbipyridine at lysine-55. The rate constant for intracomplex 
      electron transfer from heme c to Cu(A) was decreased from 40000 s(-1) for 
      wild-type CcO to 16000 s(-1) and 11000 s(-1) for the M263L and H260N mutants, 
      respectively. The rate constant for electron transfer from Cu(A) to heme a was 
      decreased from 90000 s(-1) for wild-type CcO to 4000 s(-1) for the M263L mutant 
      and only 45 s(-1) for the H260N mutant. The rate constant for the reverse 
      reaction, heme a to Cu(A), was calculated to be 66000 s(-1) for M263L and 180 
      s(-1) for H260N, compared to 17000 s(-1) for wild-type CcO. It was estimated that 
      the redox potential of Cu(A) was increased by 120 mV for the M263L mutant and 90 
      mV for the H260N mutant, relative to the potential of heme a. Neither mutation 
      significantly affected the binding interaction with cytochrome c. These results 
      indicate that His-260, but not Met-263, plays a significant role in electron 
      transfer between Cu(A) and heme a.
FAU - Wang, Kefei
AU  - Wang K
AD  - Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, 
      Arkansas 72701, USA.
FAU - Geren, Lois
AU  - Geren L
FAU - Zhen, Yuejun
AU  - Zhen Y
FAU - Ma, Ling
AU  - Ma L
FAU - Ferguson-Miller, Shelagh
AU  - Ferguson-Miller S
FAU - Durham, Bill
AU  - Durham B
FAU - Millett, Francis
AU  - Millett F
LA  - eng
GR  - 1 P20 RR15569/RR/NCRR NIH HHS/United States
GR  - GM20488/GM/NIGMS NIH HHS/United States
GR  - GM26916/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 (Ligands)
RN  - 0 (Organometallic Compounds)
RN  - 4QD397987E (Histidine)
RN  - 7006-34-0 (Asparagine)
RN  - 789U1901C5 (Copper)
RN  - 7UI0TKC3U5 (Ruthenium)
RN  - AE28F7PNPL (Methionine)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
RN  - GMW67QNF9C (Leucine)
SB  - IM
MH  - Amino Acid Substitution/genetics
MH  - Asparagine/genetics
MH  - Binding Sites/genetics
MH  - Copper/*metabolism
MH  - Electron Transport/genetics
MH  - Electron Transport Complex IV/chemistry/*genetics/*metabolism
MH  - Histidine/genetics
MH  - Kinetics
MH  - Leucine/genetics
MH  - Ligands
MH  - Methionine/genetics
MH  - Organometallic Compounds/chemistry
MH  - Photolysis
MH  - Rhodobacter sphaeroides/*enzymology/*genetics
MH  - Ruthenium/chemistry
MH  - Ultracentrifugation/methods
EDAT- 2002/02/14 10:00
MHDA- 2002/03/28 10:01
CRDT- 2002/02/14 10:00
PHST- 2002/02/14 10:00 [pubmed]
PHST- 2002/03/28 10:01 [medline]
PHST- 2002/02/14 10:00 [entrez]
AID - bi0114630 [pii]
AID - 10.1021/bi0114630 [doi]
PST - ppublish
SO  - Biochemistry. 2002 Feb 19;41(7):2298-304. doi: 10.1021/bi0114630.