InteraccionesProteína - Proteína
Fuertes (t = s, min) Complejos proteicos (estables)
Débiles (t = s, ms)Complejo intermediario (transitorio)en una reacción enzimática
Schwikowski et al.(2000) Nature Biotech. 18, 1257 - 1261
Interactions between functional groups
Interactions between proteins of different compartments
Schwikowski et al.(2000) Nature Biotech. 18, 1257 - 1261
Tong et al. (2002) Science 295, 321-324
Yeast SH3 domains — which recognize proline-rich peptides — generated a network containing 394 interactions among 206 proteins
An interaction map of the yeast proteome assembled from published interactions
Schwikowski et al.(2000) Nature Biotech. 18, 1257 - 1261
..\..\LINKS\Ho Nature(2002).pdf
Ho et al. (2002) Nature 415, 180
Protein network in Saccharomyces cerevisiae
Kumar & Snyder (2002) Nature 415, 123-124Ho, Y et al. (2002) Nature 415, 180 - 183
Analysing protein interactions:Systematic identification of protein complexes in Saccharomyces cerevisiae by mass spectrometry
T. Iiri et al. (1998) Nature 394, 35-38
How does a trimeric G protein on the inside of a cell membrane respond to activation by a transmembrane receptor?
Trimeric () G proteins relay signals from transmembrane receptors to intracellular enzymesand ion channels, thereby mediating vision, smell, taste and the actions of many hormones andneurotransmitters
T. Iiri et al. (1998) Nature 394, 35-38
The GTPase cycle of trimeric G proteins
The 'turn-on' step begins when the activated receptor (R*) associates with the trimer of (GDP), causing dissociation of GDP. Then GTP binds to the complex of R* with the trimer in its 'empty' state (e), and the resulting GTP-induced conformational change causes GTP to dissociate from R* and from . After the 'turn-off' step (hydrolysis of bound GTP to GDP and inorganic phosphate, Pi), GDP reassociates with .
T. Iiri et al. (1998) Nature 394, 35-38
Contacts between G (left) and G-GDP (right)
Red dashed lines indicate contacts that appear to be required for receptor activation but not for G–G association; green dashed lines indicate contacts that are important for both functions
T. Iiri et al. (1998) Nature 394, 35-38
How does a trimeric G protein on the inside of a cell membrane respond to activation by a transmembrane receptor?
Biomedical relevance:G-protein mutations in patients with hypertension and inherited endocrine disorders enhance or block signals from stimulated receptors.
A. Chiarugi & M.A. Moskowitz (2002) Science 297, 200
PARP-1: A Perpetrator of Apoptotic Cell Death
Apoptotic cell death is triggered by activation of the nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1).
Through unknown mechanisms, PAR formation and NAD+ depletion may trigger a cascade of events.
PS II
h
e
e*
cyt b6-fcomplex
OUT
IN
H2O
QPS I
h
e
e*
Pc (Cu )+
cyt c6 (Fe )2+
Fd
Navarro et al. (1997) J. Biol. Inorg. Chem. 2, 11-22
Cyt c6Pc
PS I
b6f
PSI-driven Electron Transfer
Fdlight
CytPc
From Cytochrome c6 to Plastocyanin
II IIII
II IIII
Navarro et al. (1997) J. Biol. Inorg. Chem. 2, 11-22
PROKARYOTES
Time (109 years ago)4 3 2 1 0
Atm
osph
eric
Lev
el(f
ract
ions
of 2
1% v
/v)
0.001
0.01
0.1
1
(Adapted from Peschek, 1996)
Oxygen content of the earth's atmosphere
EUKARYOTESPhotosyntheticO2 production
Pasteur Point(O2 respiration)
Berkner-Marshall Point(Terrestrial life)
Cu
FeS2-
SO42-
Time (109 years ago)4 3 2 1 0
Ava
ilabi
lity
(Adapted from Williams & Silva, 1997)
Plastocyanin
Cu ligands:His-35 Cys-84 His-87 Met-92
Heme ligands:His-19 Met-61
Cytochrome c6
___________________________________________________
Organism Protein pI___________________________________________________
Spinach Plastocyanin 4.2
Monoraphidium Plastocyanin 3.7 Cytochrome c6
3.6
Anabaena Plastocyanin 9.0 Cytochrome c6
9.0
Synechocystis Plastocyanin 5.5 Cytochrome c6 5.6
____________________________________________________
Isoelectric point of cytochrome c6 and plastocyaninisolated from different organisms
Cytochrome c6
Plastocyanin
De la Rosa et al. (2002) Bioelectrochemistry 55, 41-45
Photosyntheticorganisms growingunder controlledconditions
A
= 2
x 10
-3
Spinach PC
Monoraphidium PC
Monoraphidium Cyt c6
Anabaena PC
Synechocystis PC
200 s
200 s
200 s
7 ms
500 s
A =
2 x
10-3
Routes
c: 1 2 3 3' 4hb: 1 2 2' 3' 4ha: 1 1' 2' 3' 4h
Protred + PSIred1
[Protred ... PSIred]*KR
3
Protox + PSIred
ket
4
[Protred ... PSIox]*
h
3'Protred + PSIox [Protred ... PSIox]
h h
K'RK'A
1' 2'
[Protred ... PSIred]KA
2
De la Rosa et al. (2002) Bioelectrochemistry 55, 41-45
KINETIC TYPES FOR THE REACTION MECHANISM
Type I
Protred + PSIox Protox + PSIred
Type II
Protred + PSIox [Protred ... PSIox] Protox + PSIred
Type III
Protred + PSIox [Protred ... PSIox] [Protred ... PSIox]* Protox + PSIred
KINETIC TYPES FOR THE REACTION MECHANISM
Type I
Protred + PSIox Protox + PSIred
Type II
Protred + PSIox [Protred ... PSIox] Protox + PSIred
Type III
Protred + PSIox [Protred ... PSIox] [Protred ... PSIox]* Protox + PSIred
KINETIC TYPES FOR THE REACTION MECHANISM
Type I
Protred + PSIox Protox + PSIred
Type II
Protred + PSIox [Protred ... PSIox] Protox + PSIred
Type III
Protred + PSIox [Protred ... PSIox] [Protred ... PSIox]* Protox + PSIred
KINETIC TYPES FOR THE REACTION MECHANISM
Type I
Protred + PSIox Protox + PSIred
Type II
Protred + PSIox [Protred ... PSIox] Protox + PSIred
Type III
Protred + PSIox [Protred ... PSIox] [Protred ... PSIox]* Protox + PSIred
Navarro et al. (1997) J. Biol. Inorg. Chem. 2, 11-22
Flexibilidad estructural de la plastocianina
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