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hello

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uh good whatever time it is wherever you

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are

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uh my name is julianna de giacomo i work

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with brock lewis university

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and i'm going to be discussing the

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environment as a driving force in the

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coevolution of pharadox and termini

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but first we are going to take a step

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backwards to really contextualize

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the significance of this claim

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biological redox reactions are catalyzed

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in nature by a set of enzymes called

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oxoduct cases this grouping can be

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separated into six major subsets which i

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have included here

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each with really diverse redox

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functionalities

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the origin of oxoroductase is likely

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parallels with the origins of life

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itself

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for the actual path of this evolution is

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largely unknown

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because of the immense structural and

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functional diversity that i've outlined

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here

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harold 2014 suggests 10 distinct origins

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for oxidative death cases where

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all iron-containing axoreductases share

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a single origin

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this is especially significant as this

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group constitutes nearly 50 percent of

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all

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metal containing oxidoreductases

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so now we are just focusing on

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understanding the origins of these

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iron-containing

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proteins there are numerous protein

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folds which contain these iron hosing

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domains

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and the most ancient of which likely

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looked like excellent ferridoxin

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ferrodoxins are a subset of electrons

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transfer proteins which contain iron

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sulfur clusters

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stabilized by assisting binding motif

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therefore

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the study of the origin of ferredoxin

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serves as a proxy

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paradoxines function using a critical

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iron sulfur cluster

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life originated on earth when the levels

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of oxygen

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was limited to completely absent which

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permitted metals

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including iron to exist as soluble

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compounds in the ocean

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such as these iron silver clusters which

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really could have formed spontaneously

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also supporting the antiquity of

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ferridoxin uh

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is that the feradoxan binding fold is

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highly evolvable

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derived from the low hydrogen bond

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energy per residue this along with the

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fact

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that uh paradoxes are also ubiquitous

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uh to all life supports that feradoxin

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is also very ancient

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in terms of how this feradoxin evolves

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it is accepted that at one point

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the gene of some ancient iron sulfur

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redox protein was duplicated

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leading to a symmetric protoferidoxin

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which i've outlined at the bottom

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of this slide however

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accent ferrodoxins are asymmetric iron

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sulfur proteins

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at this point each half could have

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acquired random mutations which led to

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modern feradoxin

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or the evolution of each half could have

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been driven by

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some external force previous

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phylogenetic analysis

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um with my lab of the amino acid

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sequence

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of each independent terminus of

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ferrodoxin displays significant sequence

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of conservation unique to each

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half this suggests that the two halves

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of ferrodoxin

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evolved independently under the

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influence of some external factors

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that specifically drove certain sequence

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changes to be conserved

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in each half thus the objectives of the

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study is to

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directly to understand the external

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forces which drove independent

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coevolution of ferradoxin

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and therefore oxo reductases but more

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broadly we hope to identify

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the basic factors of electron transfer

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and

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contribute to establishing the possible

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conditions for

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the origins of life

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of course central the study is the

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hypothesis

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in this study we suppose that following

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a gene duplication event environment

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environmental factors drove the

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independent co-evolution of each

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terminus

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of ancient paradoxin we specifically

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chose to start by looking at the impacts

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of temperature and ph

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because not only are these some of the

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most simple factors of environment

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but consistent with uh the hypothesis

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that life originated at

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a deep sea hydrothermal vent temperature

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and ph are two characteristics of the

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environment of early life

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which would have drastically changed as

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life diversified

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from that point and moving forward

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for the study it was most advantageous

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for us to focus on the most ancient

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group of paradoxes

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and we find this in four iron first

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sulfur cluster feradox and specifically

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in methanogenic archaeal host organisms

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so i'm moving on to methods and results

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in order to analyze independent

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coevolution we had to split each

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feradoxin

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into its respective termini we did this

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with

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a novel methodology to my group by

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locating the halfway point

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in protein three structures and

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comparing this

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to an alignment with all relevant

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ferridoxin sequences which were analyzed

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in this study

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this created an n-terminus and

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c-terminus for

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every protein finally we arranged these

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termini

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into maximum likelihood phylogenetic

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trees which

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allowed us to analyze the evolutionary

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relationships between these proteins

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here you can see the initial

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phylogenetic tree which was generated

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from the aligned

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paradox in termini the same termini

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are generally clustered together

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indicating that they are similar

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across different proteins as you can see

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in the bottom highlighted

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clade however you're um above this you

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can see

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that there are several clades that are

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mixed showing that the termini still

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display a level of sequence similarity

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within the same proteins

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when we consider host optimal growth

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temperature data

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it appears that in the instances where

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thermophile and hypothermophile

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sequences appear to be deeply branching

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in the clade which means they are closer

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to the origin

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the sequence is typically from the c

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terminus of ferridoxin which i've

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outlined here

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you can also see that the thermophile

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and hypothermophile hosts are generally

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clustered together

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whether they are at the closer to the

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origin or

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uh elsewhere in the tree unfortunately

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no such

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correlations existed when data ph data

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further investigation was focused on a

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large clade that was almost

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entirely composed of feradox and termini

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this is highlighted in blue on the slide

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the

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formed four distinct clusters

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the sister alpha beta gamma and delta

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while there are no differential

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distribution of ph

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among these sister clades we do see a

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pretty

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clear-cut distribution with temperature

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where

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especially sister-clad gamma is really

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dominated by hypothermophiles and

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to investigate further multiple sequence

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alignments were compared between the

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termini of each sister clade

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all alignments were visualized as

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sequence logos

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um visualized on the slide here each

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sister clade contained residues which

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were

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differentially present but the most

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notable

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was in sister clay gamma which is

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dominated by thermophiles and

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hypothermophiles i've mentioned before

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which contains a unique and really

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heavily conserved valine

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at position 5 within this termini

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and a tripeptide segment

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so now what does it all mean uh the real

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takeaway from the study is that these

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findings suggest that

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the paradox in termini did likely

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co-evolve

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independently where temperature was one

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of the driving factors for residue

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change

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in each terminus and ph as far as we

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know

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does not appear to be in such a direct

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way

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the c-termini sequence also appears to

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be more ancient

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than the n-termini and perhaps reflects

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the protoferidoxin which underwent a

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gene duplication originally

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within the c-termini a valine near the

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beginning of the sequence

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appears to be critical to thermophile

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and hypothermophile ferrodoxin

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um we also know that an ancient

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ferrodoxin

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likely evolved near the origins of life

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and is diversified

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into all iron-containing proteins

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including 50 percent of all

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metal containing oxidoreduct cases

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therefore

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this investigation also suggests that

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environmental temperature was a driving

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factor

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in the ancient evolution of life's

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really earliest oxorbectases and

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proteins that were capable of electron

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transfer

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as thermophile and hypothermia file

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sequences appear to be

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deeply branching the study also supports

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that life's earliest oxo reductases

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developed

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in organisms with extremely hot

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environments

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these and uh observations aligned with

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previous studies

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um on small subunit rna and of course

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the hypothesized origin of life at

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superheated hydrothermal vents

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and that is all i have for you today um

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i would like to

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acknowledge my uh head of my lab dr

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vikas nanda

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and everyone else in the nonda lab the

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nod to dream team

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and everyone else who

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helped with collecting source materials