Conserved amino acids in each subunit of the heteroligomeric tRNA m1A58 Mtase from Saccharomyces cerevisiae contribute to tRNA binding

In Saccharomyces cerevisiae, a two-subunit methyltransferase (Mtase) encoded by the essential genes TRM6 and TRM61 is responsible for the formation of 1-methyladenosine, a modified nucleoside found at position 58 in tRNA that is critical for the stability of tRNAiMet. The crystal structure of the homotetrameric m1A58 tRNA Mtase from Mycobacterium tuberculosis, TrmI, has been solved and was used as a template to build a model of the yeast m1A58 tRNA Mtase heterotetramer. We altered amino acids in TRM6 and TRM61 that were predicted to be important for the stability of the heteroligomer based on this model. Yeast strains expressing trm6 and trm61 mutants exhibited growth phenotypes indicative of reduced m1A formation. In addition, recombinant mutant enzymes had reduced in vitro Mtase activity. We demonstrate that the mutations introduced do not prevent heteroligomer formation and do not disrupt binding of the cofactor S-adenosyl-l-methionine. Instead, amino acid substitutions in either Trm6p or Trm61p destroy the ability of the yeast m1A58 tRNA Mtase to bind tRNAiMet, indicating that each subunit contributes to tRNA binding and suggesting a structural alteration of the substrate-binding pocket occurs when these mutations are present

Motivations and benefits of ISO system implementation in transportation-related companies: marketing aspect of ISO

The paper analyses the effects of ISO system implementation and certification. It separately reviews motivations to implement ISO system and benefits after the system implementation. The authors analyse motivations and benefits that are internal (managerial) and external (mainly - marketing type). The analysis is performed on the basis of the survey of Lithuanian companies, comparing findings with similar research in other countries. Industry (sectorial) specifics is analysed on the basis of transportation-related companies group

Automobile country of origin related associations in Lithuanian market

Automobile is a high-involvement product that typically requires significant buyer’s attention when purchased. It is typical that country of origin (COO) of a purchased car is considered among other product characteristics. hough COO concept is analysed for decades, many factors allow to explore this issue again. First, globalization factors influence importance of COO. Second, products have certain specifics, and COO is not equally influencing buyers’ decisions in all cases. Third, countries have some stereotype images, which vary among different groups. And finally, buyers themselves are ‘products’ of certain historical and economic developments of their environment, which predetermine their beliefs and associations. Analysis of attitudes about automobile COO and related associations among Lithuanian middle-level managers represents specifics of a country that was fully exposed to products of the international automotive industry just for about a decade

Screening the Budding Yeast Genome Reveals Unique Factors Affecting K2 Toxin Susceptibility

Background: Understanding how biotoxins kill cells is of prime importance in biomedicine and the food industry. The budding yeast (S. cerevisiae) killers serve as a convenient model to study the activity of biotoxins consistently supplying with significant insights into the basic mechanisms of virus-host cell interactions and toxin entry into eukaryotic target cells. K1 and K2 toxins are active at the cell wall, leading to the disruption of the plasma membrane and subsequent cell death by ion leakage. K28 toxin is active in the cell nucleus, blocking DNA synthesis and cell cycle progression, thereby triggering apoptosis. Genome-wide screens in the budding yeast S. cerevisiae identified several hundred effectors of K1 and K28 toxins. Surprisingly, no such screen had been performed for K2 toxin, the most frequent killer toxin among industrial budding yeasts. Principal Findings: We conducted several concurrent genome-wide screens in S. cerevisiae and identified 332 novel K2 toxin effectors. The effectors involved in K2 resistance and hypersensitivity largely map in distinct cellular pathways, including cell wall and plasma membrane structure/biogenesis and mitochondrial function for K2 resistance, and cell wall stress signaling and ion/pH homeostasis for K2 hypersensitivity. 70% of K2 effectors are different from those involved in K1 or K28 susceptibility. Significance: Our work demonstrates that despite the fact that K1 and K2 toxins share some aspects of their killing strategies, they largely rely on different sets of effectors. Since the vast majority of the host factors identified here is exclusively active towards K2, we conclude that cells have acquired a specific K2 toxin effectors set. Our work thus indicates that K1 and K2 have elaborated different biological pathways and provides a first step towards the detailed characterization of K2 mode of action. © 2012 Servienė et al.SCOPUS: ar.jinfo:eu-repo/semantics/publishe