PMID- 16411750
OWN - NLM
STAT- MEDLINE
DCOM- 20060417
LR  - 20181113
IS  - 0006-2960 (Print)
IS  - 1520-4995 (Electronic)
IS  - 0006-2960 (Linking)
VI  - 45
IP  - 3
DP  - 2006 Jan 24
TI  - Photolabeling of cardiolipin binding subunits within bovine heart cytochrome c 
      oxidase.
PG  - 746-54
AB  - Subunits located near the cardiolipin binding sites of bovine heart cytochrome c 
      oxidase (CcO) were identified by photolabeling with arylazido-cardiolipin 
      analogues and detecting labeled subunits by reversed-phase HPLC and 
      HPLC-electrospray ionization mass spectrometry. Two arylazido-containing 
      cardiolipin analogues were synthesized: (1) 2-SAND-gly-CL with a nitrophenylazido 
      group attached to the polar headgroup of cardiolipin (CL) via a linker containing 
      a cleavable disulfide; (2) 2',2''-bis-(AzC12)-CL with two of the four fatty acid 
      tails of cardiolipin replaced by 12-(N-4-azido-2-nitrophenyl) aminododecanoic 
      acid. Both arylazido-CL derivatives were used to map the cardiolipin binding 
      sites within two types of detergent-solubilized CcO: (1) intact 13-subunit 
      CL-containing CcO (three to four molecules of endogenous CL remain bound per CcO 
      monomer); (2) 11-subunit CL-free CcO (subunits VIa and VIb are missing because 
      they dissociate during CL removal). Upon the basis of these photolabeling 
      studies, we conclude that (1) subunits VIIa, VIIc, and possibly VIII are located 
      near the two high-affinity cardiolipin binding sites, which are present in either 
      form of CcO, and (2) subunit VIa is located adjacent to the lower affinity 
      cardiolipin binding site, which is only present in the 13-subunit form of CcO. 
      These data are consistent with the recent CcO crystal structure in which one 
      cardiolipin is located near subunit VIIa and a second is located near subunit VIa 
      (PDB ID code referenced in Tomitake, T. et al. (2003) Proc. Natl. Acad. Sci. 
      U.S.A. 100, 15304-15309). However, we propose that a third cardiolipin is bound 
      between subunits VIIa and VIIc near the entrance to the D-channel. Cardiolipin 
      bound at this location could potentially function as a proton antenna to 
      facilitate proton entry into the D-channel. If true, it would explain the CcO 
      requirement of bound cardiolipin for full electron transport activity.
FAU - Sedlak, Erik
AU  - Sedlak E
AD  - Department of Biochemistry, The University of Texas Health Science Center, 7703 
      Floyd Curl Drive, San Antonio, Texas 78229-3900, USA.
FAU - Panda, Markandeswar
AU  - Panda M
FAU - Dale, Marsha P
AU  - Dale MP
FAU - Weintraub, Susan T
AU  - Weintraub ST
FAU - Robinson, Neal C
AU  - Robinson NC
LA  - eng
GR  - R01 GM024795/GM/NIGMS NIH HHS/United States
GR  - R01 GM024795-25/GM/NIGMS NIH HHS/United States
GR  - GMS 24795/PHS HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Cardiolipins)
RN  - 0 (Protein Subunits)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Animals
MH  - Binding Sites
MH  - Cardiolipins/chemistry/*metabolism
MH  - Cattle
MH  - Electron Transport Complex IV/*chemistry/*metabolism
MH  - Light
MH  - Molecular Structure
MH  - Myocardium/*enzymology
MH  - Protein Binding
MH  - Protein Subunits/chemistry/metabolism
MH  - Staining and Labeling/*methods
PMC - PMC2561917
MID - NIHMS30546
EDAT- 2006/01/18 09:00
MHDA- 2006/04/18 09:00
PMCR- 2008/10/06
CRDT- 2006/01/18 09:00
PHST- 2006/01/18 09:00 [pubmed]
PHST- 2006/04/18 09:00 [medline]
PHST- 2006/01/18 09:00 [entrez]
PHST- 2008/10/06 00:00 [pmc-release]
AID - 10.1021/bi050870z [doi]
PST - ppublish
SO  - Biochemistry. 2006 Jan 24;45(3):746-54. doi: 10.1021/bi050870z.