Ribozymes history essay help Health Medical

Structure: The ribozymes are classified into different categories; some of them are like hammerhead ribozyme (Fig. l) and hairpin ribozyme (Fig. 2) as shown in the figures below. 2) Mode of Action: Ribozyme is an RNA molecule (ribonucleic acid enzyme) that has some biochemical and catalytic functions similar to the enzymatic ones. These RNA molecules are antisense RNA that targets a specific RNA sequence and upon base-pairing with the sense RNA, it inactivates it by cleaving the phosphodiester bond at a specific site (Ribozyme… ).

All enzymes have very specific binding characteristic which also is a feature that ribozymes has which make them act as a catalyst. There are many categories of Ribozymes based on its different structures, function and mechanism of interaction. The first two discovered structures of Ribozymes are the Tetrahymena and RNase P. During a study done on the protozoan Tetrahymena Thermophila, the RNA showed that it can act as a protein that catalyzes the splicing step and it was categorized as Group I introns which reflects the mechanism of the ibozyme RNA.

There are also the hammerhead ribozyme, the hairpin ribozyme and the hepatitis delta virus ribozyme (Ribozyme… ). Figure 3 It snows now ribozymes functioning. bind and cleave mR NA to prevent it trom The RNase P is a protein that has an active RNA molecule that cuts around 60 tRNA that is very essential for the DNA translation processes (Ribozymes, 2002). Another example for the early-discovered ribozymes is the L 19 R from the protozoan Tetrahymena. This ribozyme cleaves itself from the precursor RNA, it is an intron with 414 bases.

A guanine nucleotide binds to the 5′ end of this intro then a 3′-OH forms at the 3′ end of the intron which causes the intro to disassociate (Ribozyme, 2002) 3) Processes which Ribozymes are involved in (Functions): The different processes, ribozymes main functions, depend on the type of ribozyme. For example Group I self-splicing introns which include the Tetrahymena ribozyme catalyze their own splicing leaving the exons together (Zeman, 2003). There is also a second class of self-splicing introns called class II however it recognizes a different et of sequence (Zeman, 2003).

These ribozymes are used to fragment/degrade mRNA molecules that are not needed by the cell. Another example is the RNase P (which is an ribozyme and protein at the same time) which is found in almost all cells (Zeman, 2003). It is believed that even with the disassociation of the ribozyme from the protein, the ribozyme can still cleave specific sequences on mRNA molecules (Zeman, 2003). Other function of ribozymes are chaperoning metal ions, they used to be identified as nly metalloenzymes which is the main molecular machine of protein translation.

These ion metals are bound to the RNA tertiary structural motif (ribozyme) which is an vital component in protein translation (Zeman, 2003) Figure 4 Group I & II selt-splicing i Ilustration. An example of the hammerhead structured ribozyme is the viroids which are circular RNA molecules that are transcribed from the genome in a circular structure then they get fragmented and these little pieces are then replicate themselves and use he plants’ needed nucleotides which affect the growth of the plant, in addition than these over-proliferation of these little fragments are then accumulate like a tumor inside the plant tissue.

Mode of action of these hammerhead RNA molecules are basically through a sequence which is less than 30 nucleotides in length and in this sequence there are 3 stems (hammerhead structure) that can cleavage very specific RNA sequences. Nowadays they are producing similar synthetic hammerhead ribozyme to target certain genome virus with less number of active nucleotides (Ribozymes, 2002).