Ribozymes

Zoko, Nikolina (2009) Ribozymes. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

Ribozymes are catalytic molecules, which must be folded into highly ordered tertiary folds, as the protein enzymes did to carry out their function. The ultimate objective is to bring the nucleophile and the scissile phosphate together and activate them. The nucleolytic ribozymes have inner-nucleotide nucleophile and scissile phosphate, and have relatively simple structures, thus the active structure is more readily formed. The nucleophile and scissile phosphate of large ribozymes are either remotely separated or in different molecules, thus it’s more complicated for them to recognize the splicing site and bring the substrate to the active site. Metal ions and protein factors are usually involved in the folding of the large ribozymes. For instance, Mg2+ is required in the substrate binding and the resolution of the highly charged active site of RNase P. The major-ity of group II introns need protein factors to assist their folding. More importantly, large ribozymes like RNase P, group I and group II ribozymes are metalloenzymes, in which metal ions directly participate in ca-talysis. Based on the fundamental reaction the majority of the ribozymes carry out, which catalyze site-specific cleavage or ligation of target RNA, and on the fact that many ribozymes function in trans, ribozymes are applied in gene therapy, by digesting the mRNA of target genes or by rescuing defective genes. There is a hypothesis about existance of a RNA world on Earth, which preceded DNA and protein world. Many experiments were made recently that give possible evidences for such hypothesis. Most likely there was some kind of a replicase ribozyme which represented that RNA world because it had features of autoreplication and catalysis. In spite of these experiments, there are no certain evidences which could prove this hypothesis about existance of a RNA world.

Item Type: Thesis (Bachelor's thesis)
Supervisor: Kalafatić, Mirjana
Date: 2009
Number of Pages: 21
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Silvana Šehić
Date Deposited: 18 Dec 2014 10:38
Last Modified: 18 Dec 2014 10:38
URI: http://digre.pmf.unizg.hr/id/eprint/3542

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