Functional analysis of substrate and cofactor complex structures of a thymidylate synthase-complementing protein

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• Thymidylate synthase-complementing proteins (TSCPs) are essential for prokaryotic cell survival when external thymidylate is unavailable.
• Unlike eukaryotic thymidylate synthase (TS), the catalytic mechanism of TSCPs remains largely uncharacterized.
• This study focuses on understanding the structure and function of a novel enzyme family crucial for microbial metabolism.

Purpose of the Study:

• To elucidate the structural and functional characteristics of a Thermotoga maritima TSCP.
• To investigate the enzyme's interactions with its substrate, analogs, and cofactor.
• To provide a foundation for the rational design of potential TSCP inhibitors.

Main Methods:

• X-ray crystallography was employed to determine the structures of the TSCP and its complexes.
• Biochemical assays were used to analyze enzyme activity and substrate binding.
• Comparative structural analysis was performed to identify conserved features within the TSCP family.

Main Results:

• The crystal structures of Thermotoga maritima TSCP, complexed with substrate, analogs, and cofactor, were determined.
• A novel helix-loop-strand motif responsible for FAD binding was identified, characteristic of the TSCP family.
• Conserved hydrophobic core residues suggest a common structural fold across different TSCPs.

Conclusions:

• The reported structures offer insights into the catalytic mechanism of TSCPs.
• The findings pave the way for the development of targeted inhibitors against these essential prokaryotic enzymes.
• Understanding the conserved structural elements aids in predicting the function and designing inhibitors for related enzymes.