PMID- 10026158
OWN - NLM
STAT- MEDLINE
DCOM- 19990318
LR  - 20190508
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 9
DP  - 1999 Feb 26
TI  - Relocating the active site of activated protein C eliminates the need for its
      protein S cofactor. A fluorescence resonance energy transfer study.
PG  - 5462-8
AB  - The effect of replacing the gamma-carboxyglutamic acid domain of activated
      protein C (APC) with that of prothrombin on the topography of the membrane-bound 
      enzyme was examined using fluorescence resonance energy transfer. The average
      distance of closest approach (assuming kappa2 = 2/3) between a fluorescein in the
      active site of the chimera and octadecylrhodamine at the membrane surface was 89 
      A, compared with 94 A for wild-type APC. The gamma-carboxyglutamic acid domain
      substitution therefore lowered and/or reoriented the active site, repositioning
      it close to the 84 A observed for the APC. protein S complex. Protein S enhances 
      wild-type APC cleavage of factor Va at Arg306, but the inactivation rate of
      factor Va Leiden by the chimera alone is essentially equal to that by wild-type
      APC plus protein S. These data suggest that the activities of the chimera and of 
      the APC.protein S complex are equivalent because the active site of the chimeric 
      protein is already positioned near the optimal location above the membrane
      surface to cleave Arg306. Thus, one mechanism by which protein S regulates APC
      activity is by relocating its active site to the proper position above the
      membrane surface to optimize factor Va cleavage.
FAU - Yegneswaran, S
AU  - Yegneswaran S
AD  - Department of Medical Biochemistry and Genetics, Texas A&M University Health
      Sciences Center, College Station, Texas 77843-1114, USA.
FAU - Smirnov, M D
AU  - Smirnov MD
FAU - Safa, O
AU  - Safa O
FAU - Esmon, N L
AU  - Esmon NL
FAU - Esmon, C T
AU  - Esmon CT
FAU - Johnson, A E
AU  - Johnson AE
LA  - eng
GR  - R01 HL 29807/HL/NHLBI NIH HHS/United States
GR  - R01 HL 32934/HL/NHLBI NIH HHS/United States
GR  - R37 HL 30340/HL/NHLBI NIH HHS/United States
GR  - etc.
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
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 (Membranes, Artificial)
RN  - 0 (Phospholipids)
RN  - 0 (Protein C)
RN  - 0 (Protein S)
RN  - TPY09G7XIR (Fluorescein)
SB  - IM
MH  - Binding Sites
MH  - Chromatography, Gel
MH  - Energy Transfer
MH  - Fluorescein
MH  - Fluorescence
MH  - Humans
MH  - Membranes, Artificial
MH  - Phospholipids/metabolism
MH  - Protein C/*metabolism
MH  - Protein S/*metabolism
MH  - Spectrometry, Fluorescence
EDAT- 1999/02/20 00:00
MHDA- 1999/02/20 00:01
CRDT- 1999/02/20 00:00
PHST- 1999/02/20 00:00 [pubmed]
PHST- 1999/02/20 00:01 [medline]
PHST- 1999/02/20 00:00 [entrez]
AID - 10.1074/jbc.274.9.5462 [doi]
PST - ppublish
SO  - J Biol Chem. 1999 Feb 26;274(9):5462-8. doi: 10.1074/jbc.274.9.5462.