Download Slides on ancient paralogs

The Ribosomal “Tree of Life”
Cenancestor
(aka LUCA or MRCA)
can be placed using the echo
remaining from the early
expansion of the genetic code.
• reflects only a single
cellular component
• no reticulation
• only extant lineages
• branch length is not
proportional to time
Deep Paralogs
• Gene families evolve by duplication,
gene transfer and divergence
• For ancient proteins, some of these
divergences occurred before the
divergence of the three domains of life
(MRCA);
• Determining function of paralog
ancestors could elucidate primordial
physiology… however, lack of time
machine prevents direct experimental
observation.
• In some special cases, can be inferred
using amino acid composition…
Catalytic subunits
Non catalytic subunits
speciation
time
gene duplication
Gogarten et al, 1989, PNAS 86, 17, 6661–6665
http://www.pnas.org/content/113/32/E4654.full.pdf?with-ds=yes
ATPase / ATPsynthase
ATP binding Subunits
B
A
A
B
B
V-proteolipid
A
C
N
c
A-proteolipids
A-type ATPase
N
a
b
b
a
N
V-type ATPase
a
C
C
Halobacterium
Methanococcus
Methanopyrus
b
c
F-type ATPase
F-proteolipid
N
C
12 proteolipid Ds / 3 catalytic SU =
4H+(Na+) / ATP
6 proteolipid Ds / 3 catalytic SU =
2H+(Na+) / ATP
Reversible Enzyme
Dedicated Ion Pump
Reversible Enzyme
Bacteria
Eukarya
Archaea
12 proteolipid Ds / 3 catalytic SU =
4H+(Na+) / ATP
endosymbionts
thermophilic
mesophilic
E
D
5
4
?
C
B
12 proteolipid Ds / 3 catalytic SU =
4H+(Na+) / ATP
Reversible Enzyme
A
3
12 proteolipid Ds / 6 catalytic SU =
2 H+(Na+) / ATP
2
Dedicated Ion Pump
1
Evolution of the Ribosome
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●
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“Core” of ribosome consists of RNA + subset of
ribosomal proteins universally conserved in all life
(~29 proteins) (Harris et al., 2003)
mRNA, tRNA, rRNA all crucial components for
translation
Catalytic peptidyltransferase activity is RNAmediated
Likely coevolved with genetic code within an RNA
world (Wolf & Koonin, 2007)
Rooting the Ribosomal Tree of Life using an Echo from the Early
Expansion of the Genetic Code
(Fournier and Gogarten, MBE 2010)