[3] This type of cap, with just the (m7G) in position is called a cap 0 structure. The ribose of the adjacent nucleotidemay also be methylated to give a cap 1. Methylation of nucleotides downstream of the RNA molecule produce cap 2, cap 3 structures and so on. In these cases the methyl groups are added to the 2' OH groups of the ribose sugar. The cap protects the 5' end of the primary RNA transcript from attack by ribonucleases that have specificity to the 3'5'phosphodiester bonds.[4] [edit]3' Processing Main article: Polyadenylation [edit]Cleavage and Polyadenylation The pre-mRNA processing at the 3' end of the RNA molecule involves cleavage of its 3' end and then the addition of about 250 adenine residues to form a poly(A) tail. The cleavage and adenylation reactions occur if a polyadenylation signal sequence (5'- AAUAAA-3') is located near the 3' end of the pre-mRNA molecule, which is followed by another sequence, which is usually (5'-CA-3')
[3] This type of cap, with just the (m7G) in position is called a cap 0 structure. The ribose of the adjacent nucleotidemay also be methylated to give a cap 1. Methylation of nucleotides downstream of the RNA molecule produce cap 2, cap 3 structures and so on. In these cases the methyl groups are added to the 2' OH groups of the ribose sugar. The cap protects the 5' end of the primary RNA transcript from attack by ribonucleases that have specificity to the 3'5'phosphodiester bonds.[4] [edit]3' Processing Main article: Polyadenylation [edit]Cleavage and Polyadenylation The pre-mRNA processing at the 3' end of the RNA molecule involves cleavage of its 3' end and then the addition of about 250 adenine residues to form a poly(A) tail. The cleavage and adenylation reactions occur if a polyadenylation signal sequence (5'- AAUAAA-3') is located near the 3' end of the pre-mRNA molecule, which is followed by another sequence, which is usually (5'-CA-3')
no conditioned response ; AVP ; 3 max [9] 130. (a) plasmid DNA protein nucleotides / sugar + phosphate + base ; amino acids ; 4 different subunits ; 20 different subunits ; phosphodiester bonds ; A phosphoester peptide bonds / polypeptide ; contains P ; contains S / disulphide bonds ; double-stranded / double helix ; may have 4º structure ; circular ; ref to, 2º / 3º, structure / AW ; AVP ; e.g. role of H bonds 3 max
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