Capping Process
The starting point is the unaltered 5′ end of an RNA molecule. This features a final nucleotide followed by three phosphate groups attached to the 5′ carbon.
- One of the terminal phosphate groups is removed (by RNA terminal phosphatase), leaving two terminal phosphates.
- GTP is added to the terminal phosphates (by a guanylyl transferase), losing two phosphate groups (from the GTP) in the process. This results in the 5′–5′ triphosphate linkage.
- The 7-nitrogen of guanine is methylated (by a methyl transferase).
- If the second base from the terminal is adenine, it can be methylated; and the third base from the terminal is generally methylated 10–15% of the time.
Read more about this topic: Five Prime Cap
Famous quotes containing the word process:
“The moralist and the revolutionary are constantly undermining one another. Marx exploded a hundred tons of dynamite beneath the moralist position, and we are still living in the echo of that tremendous crash. But already, somewhere or other, the sappers are at work and fresh dynamite is being tamped in place to blow Marx at the moon. Then Marx, or somebody like him, will come back with yet more dynamite, and so the process continues, to an end we cannot foresee.”
—George Orwell (19031950)
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