“You got to know when to hold ‘em,
know when to fold ‘em,
know when to walk away,
and know when to run.”
–Kenny Rogers
Ribosomes translate a linear messenger RNA sequence into a linear amino acid sequence. The amino acid chain emerges from the exit tunnel of the ribosome as a “nascent polypeptide chain.” The chain of amino acids undergoes a complex folding operation starting within the exit tunnel itself (asamonitor.pub/3AxVJP6).
The folding proceeds until the mRNA has been fully translated. The resulting polypeptide continues to fold until it snuggles itself into a minimal energy conformation. This complex folding is guided by small proteins called chaperones. Chaperones ensure that the final protein 3D structure is in its minimal energy conformation, the biologically active form.
Occasionally the final confirmation of the protein isn't the active form. Instead, the protein has found another way to curl...