Inside
Every one of your cells
Trillions of copies
You have a protein
Named histone h3
Goes by 3.1
Or by 3.3
At the very "beginning"
Of this protein
Are short structural domains
Like artk
Or similar amino acids
These 4 amino acids
In 4 copies
Sit amidst
20 other amino acids
These structures
Are critical for life
To succeed
The arginine = "r"
Is methylated
Into me1
And me2
Sometimes symmetric
Sometimes asymmetric
Several enzymes methylate
And demethylate
While right next door
The threonine = "t"
Or serine, sometimes,
Gets phosphorylated
By other enzymes
Known as kinases
And the phosphate removed
Occasionally
By phosphatases.
The "k" is lysine
And lysine is important
Because it can be acetylated.
And deacetylated.
And methylated once,
Twice, or three times
Me1, me2 or me3
By acetyltransferases
And deacetylases
And methyltransferases
And demethylases
Dozens of enzymes
Constantly change
The chemistry
And structure
Of this protein's
Amino terminus
This code
A complex dance
Of biochemistry and mind
Is read
By other proteins
Which help
Distribute the activities
Coordinating
Machines
Enzymes
To open up your dna
And allow
Your genes
To be
Turned on
Or silenced
Exactly
As the cell
Needs...
Four amino acids
Of the twenty
Allow this to happen
Just by occurring
Next to
Each other
On one or more proteins
Inside your nucleus
Inside your cells
With dna wrapped
Around it
This protein
Histone h3.1
Or 3.3
Combines with itself
And 6 other protein subunits
To form an octamer
2 molecules h2a
2 molecules h2b
2 molecules h3
2 molecules of h4
Positively charged
Fat with lysine
They wrap your dna
Two times around
A protein spool
And save space
In doing so
2 meters
Of dna
Inside each one
Of your little cells
Your littler nuclei
Are fat with code
Both linear
And structural
From dna
From rna
And from the histones
We call this chromatin
I sell chromatin
In many combinations
We all explore
The landscape
Of chromatin
