Study of thymidylate synthetase-function by laser Raman spectroscopy

Area of Science:

• Biochemistry
• Molecular Biology
• Spectroscopy

Background:

• Thymidylate synthetase is a crucial enzyme in DNA synthesis.
• Understanding its structure and interactions is vital for drug development.

Purpose of the Study:

• To investigate the secondary structure of thymidylate synthetase.
• To analyze structural changes upon formation of a ternary complex with folate and fluorodeoxyuridylate.

Main Methods:

• Laser-Raman spectroscopy with 488 nm argon ion laser excitation.
• Analysis of spectral bands in the 600-1700 cm-1 range.

Main Results:

• Thymidylate synthetase exhibits a mixed alpha-helical and unordered secondary structure.
• Ternary complex formation introduces a new band at 1618 cm-1, indicative of dihydrofolate or an iminium ion.
• Local structural changes occur in carboxyl, tryptophan, and CH-x groups upon complexation, without altering overall secondary structure.

Conclusions:

• Laser-Raman spectroscopy effectively probes enzyme structure and ligand binding.
• The study provides insights into the mechanism of thymidylate synthetase inhibition.