Folding
Protein folding is a spontaneous process that proceeds by trial and error. The synthesis of almost all
proteins begins in the cell cytoplasm, where the ribosomes, with the help of tRNAs, translate the mRNAs
into amino acid stretches which constitute the primary structure of the proteins in formation. As soon as
the N-terminus of the protein begins to escape from the ribosome, the amino acids that compose it begin
to interact with each other and form hydrogen bonds and intramolecular hydrophobic interactions in order
to minimize unfavorable interactions with the surrounding environment and achieve conformation with the
lowest free energy content.
Splicing
Particular nuclear ribonucleoproteins called snRNP intervene in this process, which reach the pre-mRNA
while it is being transcribed and bind to it, recognizing particular sequences placed on the border between
introns and exons, called consensus sequences, for complementarity of the bases. from ATP some proteins
are added to each snRNP, thus forming a voluminous complex, called spliceosome, which cuts the pre-
mRNA, eliminates introns and reassembles the end of exons, thus producing the mature mRNA, to which
they will be added a cap and a tail to facilitate the binding with the ribosomes and to protect it from
hydrolytic enzymes that could degrade it.