PA clan
The PA clan (Proteases of mixed nucleophile, superfamily A) is the largest group of proteases with common ancestry as identified by structural homology. Members have a chymotrypsin-like fold and similar proteolysis mechanisms but sequence identity of <10%. The clan contains both cysteine and serine proteases (different nucleophiles). PA clan proteases can be found in plants,animals,fungi,eubacteria,archaea and viruses.
The PA clan represents an example of convergent evolution to the use of a catalytic triad for hydrolysis. It also is an example of extreme divergent evolution of active sites in enzymes.
History
In the 1960s, the sequence similarity of several proteases indicated that they were evolutionarily related. These were grouped into the chymotrypsin-like serine proteases (now called the S1 family). As the structures of these, and other proteases were solved by X-ray crystallography in the 1970s and 80s, it was noticed that several viral proteases such as Tobacco Etch Virus protease showed structural homology despite no discernible sequence similarity and even a different nucleophile. Based on structural homology, a superfamily was defined and later named the PA clan (by the MEROPS classification system). As more structures are solved, more protease families have been added to the PA clan superfamily.
Podcasts:
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by Boo Clan
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by Boo Clan
The Juggalette Song
by: Boo Clan(Chorus)
Nothin on this earth can rock me
Like a juggalette
Kissing up and down her neck and
Talking dirty til she gets wet
Ladies in clown makeup and
Milenko thongs listen up
I'm a spit this lyrical message
Until I've had enough
(Chorus)
Nothin on this earth can rock me
Like a juggalette
Kissing up and down her neck and
Talking dirty til she gets wet
Take this for example,
Recently there's been a lady
Gorgeous Juggalette who
I can call my brunette baby
Loves it when I hold her tight and
Stick my hands between her thighs
Tears of ecstacy and passion
Slowly drippin from her eyes
Took her panties off
And rolled my tongue right down
Her f***ing chest
To the best p***y ever tasted,
F*** it was the best
Reached up with my arms
And she grabbed and
Tightly held my hands
Telling me how good it felt
So I continued with my plans
Dug a little deeper with my tongue
Until I hit the knot
Gripped my hands tighter
As my tongue tickled her G spot
Next thing that we did was
To create one being from two
Got her up on top and
F***ed her as the Juggalos do
Never felt the passion from
Another Juggalette before
That was days ago
And I'm still here cravin more
Gotta tell this Juggalette
In some form, in some way
I still got more to say and that
Boo still wants to play
This song goes out to all of you Psychopathic Juggalettes
Listen to me closely so that
I can get this off my chest
(Chorus)
Nothin on this earth can rock me
Like a juggalette
Kissing up and down her neck and
Talking dirty til she gets wet
Juggalettes listen up,
I'm a talk about them
Silly f*ggot pop punks
Them jockey sports hunks
The ones that dress to impress
And always buy from the best
The f**k they got to offer you
Besides a shaved chest?
It's what a juggalo like me can
Offer you just every time
Pourin' Faygo down ya t! ts
As we hand you to the sweet sublime
A juggalo will strip you down and
F**k you in his facepaint
Chew off your panties and
Lick your p***y til you faint
This song goes out to all of you Psychopathic Juggalettes
Listen to me closely so that
I can get this off my chest
(Chorus)
Nothin on this earth can rock me
Like a juggalette
Kissing up and down her neck and
Talking dirty til she gets wet
This song goes out to all of you Psychopathic Juggalettes
Listen to me closely so that
I can get this off my chest
(Chorus)
Nothin on this earth can rock me
Like a juggalette
Kissing up and down her neck and
Talking dirty til she gets wet
This song goes out to all of you Psychopathic Juggalettes
Listen to me closely so that
I can get this off my chest
(Chorus)
Nothin on this earth can rock me
Like a juggalette
Kissing up and down her neck and