Assistant Professor

Dr. BC Guha centre for Genetic Engineering and Biotechnogy

University of Calcutta (Kolkata, India)

Visiting Assistant Professor

Microbiology

The Ohio State University (Columbus, OH)

Michael Ibba

Structure-function relationship of aminoacyl-tRNA synethetases (aaRSs)

The maintenance of cellular function is dependent on the fidelity with which information is transmitted from the genes to their gene products. The prevention of amino acid misincorporation into proteins is ensured by the activity of the aminoacyl-tRNA synthetase (aaRS) family of enzymes that play a fundamental role in the translation of the genetic code. AaRSs catalyze the covalent attachment of amino acids to the 3’ end of their cognate transfer RNA (tRNA). The tRNA aminoacylation reaction can be divided into two steps, In the first step amino acid is activated by ATP to form an enzyme-bound aminoacyl-adenylate intermediate (Activation step, equ 1), followed by transfer of the amino acid to the 3’ terminus of the tRNA (Transfer step, equ 2):

aaRS + ATP:Mg2+ + aa →aaRS:aa~AMP+PPi:Mg2+ (1)

aaRS:aa~AMP +tRNA→aaRS + aa-tRNA +AMP (2)

AaRSs have been studied in exceptional detail and considerable data have accumulated on the mechanism of aa-tRNA formation. In the past decade it has been found that the aaRSs have other crucial cellular functions such as cell signaling, mitochondrial disease, HIV packaging, antibiotic resistance etc. Mutations in genes encoding aaRSs have been reported to be related with neuro degeneration that evoked the question about the role of these enzymes in neural function. These additional activities beyond aminoacylation are far less well understood. Study of structure-function relationship will provide insights into the degree of functional diversity among the aaRSs in general, an emerging family of anti-microbial drug target.

2004-2005 Assistant Professor, Kalyani University

2004 Research Associate, Indian Association for the Cultivation of Science, Kolkata, India