Naslov
Functional characterisation of methyltransferase Sgm

Autori
Čubrilo, Sonja ; Maravić, Gordana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
1st MedILS Summer School, Structure and Evolution: from Bench to Terminal, Book of Abstracts / - , 2006, 25-26

Skup
1st MedILS Summer School, Structure and Evolution: from Bench to Terminal

Mjesto i datum
Split, Hrvatska, 18.07.2006. - 27.07.2006

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
aminoglycosides; resistance; methyltransferase Sgm

Sažetak
Methylation is the most frequent posttranscriptional modification found in rRNA, exerted mostly by S-adenosyl-methionine dependent methylases. Furthermore, in addition to the essential set of enzymes, some antibiotic producing bacteria as well as ever growing number of antibiotic resistant strains contain different rRNA methylases, which protect their protein synthesis machinery from the destructive action of ribosomal antibiotics. The self-defense mechanism of natural producers of deoxystreptamine-containing aminoglycoside antibiotics is methylation of a specific guanine residue within the 16S rRNA. In addition, this is a relatively new mechanism of resistance found in members of clinically important Enterobacteriaceae family and in Pseudomonas aeruginosa and Serratia marcescens clinical strains. Methylation of 16S rRNA in aminoglycoside resistant bacteria is carried out by enzymes from the aminoglycoside resistance methylase (Agr) family, which are now found to be spreading among clinical strains by rapid horizontal transfer. Very little is known on the mechanism of action of Agr methylases, while the structural data virtually do not exist. We are therefore studying the molecular basis of this mechanism, in order to help to prevent it before it becomes omnipresent, especially among multiresistant pathogens. The aim of our study is to functionally characterise the methyltransferase Sgm. We cloned the sgm gene into vectors pUC19 and pET-25b(+) and developed the assays for functional tests in vivo. We are now optimising the conditions for the methylation test in vitro. By site-directed mutagenesis we will investigate the roles of evolutionary conserved amino acids and define the localisation of the active site and cofactor S-adenosyl-methione binding site. This will enable us to propose a reaction mechanism and to gain insight into possibilities of finding a specific inhibitor that would block aminoglycoside resistance based on ribosome methylation.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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