The pharmacogenetics of NAT: structural aspects

Area of Science:

• Biochemistry
• Pharmacogenetics
• Enzymology

Background:

• Arylamine N-acetyltransferases (NATs) are key enzymes in xenobiotic metabolism, involved in detoxification and activation of drugs and carcinogens.
• NATs were first identified for their role in inactivating isoniazid, revealing early evidence of pharmacogenetic variation.
• Polymorphisms in NAT genes, often single nucleotide polymorphisms (SNPs), are the primary cause of interindividual differences in NAT activity.

Purpose of the Study:

• To explore the structural and functional significance of Arylamine N-acetyltransferases (NATs).
• To understand the role of NAT enzymes in both xenobiotic and endogenous metabolism.
• To investigate the structural basis of NAT activity and its implications for pharmacogenetics.

Main Methods:

• Analysis of existing genome sequences to identify homologous NAT members in prokaryotes and eukaryotes.
• Determination of the three-dimensional structures of Salmonella typhimurium and Mycobacterium smegmatis NATs.
• Comparative structural analysis focusing on the active site and catalytic triad (Cys-His-Asp).

Main Results:

• NAT enzymes exhibit a conserved, unique fold with a catalytic triad (Cys-His-Asp) forming the active site.
• Structural determination of prokaryotic NATs provides insights into the enzyme's conserved mechanism.
• Identification of numerous homologous NAT members across prokaryotic and eukaryotic organisms.

Conclusions:

• The determined structures of prokaryotic NATs offer a foundation for understanding the broader roles of this enzyme family.
• Structural insights into NATs can elucidate their involvement in xenobiotic and endogenous metabolic pathways.
• Further structural studies of NATs could advance understanding of pharmacogenetic variations and drug metabolism.