Naslov
Two distinct IleRS proteins in Bacillus megaterium and their possible roles in adaptation to various stress conditions

Autori
Zanki, Vladimir ; Gruić-Sovulj, Ita

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

Izvornik
HDBMB2019 - Crossroads in Life Sciences : Book of abstracts / Katalinić, Maja ; Dulić, Morana ; Stuparević, Igor - Zagreb : Hrvatsko društvo za biokemiju i molekularnu biologiju (HDBMB), 2019, 134-134

ISBN
978-953-95551-7-5

Skup
Congress of the Croatian Society of Biochemistry and Molecular Biology "Crossroads in Life Sciences" (HDBMB2019)

Mjesto i datum
Lovran, Hrvatska, 25.09.2019. - 28.09.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
isoleucyl-tRNA synthetase, Bacillus megaterium, mupirocin resistance

Sažetak
Protein biosynthesis is precisely and tightly regulated to address cellular demands under different growth conditions. Isoleucine-tRNA synthetase (IleRS) contributes to protein biosynthesis by covalent coupling of tRNAIle with isoleucine, thus providing aminoacylated tRNA for the ribosome. Several members of Bacillus genus have two types of ileS genes present in their genome: ileS1 and ileS2. The corresponding IleRS1 and IleRS2 enzymes are expected to differ in susceptibility to mupirocin. This antibiotic binds to the enzyme active site and inhibits the formation of Ile-tRNAIle. To biochemically characterize BmIleRS1 and BmIleRS2 from Bacillus megaterium, both proteins were overexpressed in Escherichia coli while specific tRNAIle isoacceptor was isolated from B. megaterium. Kinetic analysis revealed that BmIleRS2 exhibits at least 100-fold lower affinity towards mupirocin than BmIleRS1. Furthermore, mupirocin resistance is apparently gained at the expense of the affinity for isoleucine. Interaction with tRNAIle decreased BmIleRS1 affinity for isoleucine, analogously as observed for E. coli IleRS. Opposing that, interaction with tRNAIle did not further affect BmIleRS2 affinity towards isoleucine. Since tRNAIle differently modulates interaction of BmIleRS1 and BmIleRS2 with isoleucine, it is intriguing to speculate that aminoacylation mechanisms have distinctly evolved to account for the trade-off between mupirocin resistance and amino acid affinity. To elucidate reasons for the presence of both ileS genes in the genome, we created knockout strains lacking either bmileS1 or bmileS2. Although both strains were viable, they however exhibited a different biofilm phenotype. Thus, it appears that both proteins have a role in adaptation to specific stress conditions ; BmIleRS2 for resistance to mupirocin and BmIleRS1 for biofilm formation. However, a crosstalk between BmIleRS1 and biofilm formation is not yet understood. Kinetic analyses and in vivo experiments are on-going to further address advantages of having both ileS genes in B. megaterium.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Biologija

POVEZANOST RADA