4L6H

Crystal structure of the Candida albicans Methionine Synthase in complex with Methotrexate and Homocysteine

4L6H の概要

• エントリーDOI: 10.2210/pdb4l6h/pdb
• 関連するPDBエントリー: 4L5Z 4L61 4L64 4L65 4L6O
• 分子名称: 5-methyltetrahydropteroyltriglutamate--homocysteine methyltransferase, ZINC ION, 2-AMINO-4-MERCAPTO-BUTYRIC ACID, ... (5 entities in total)
• 機能のキーワード: cobalamin-independent, surface entropy reduction, fungal, dual tim barrels, methionine synthase, transferase
• 由来する生物種: Candida albicans SC5314
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 88843.99

構造登録者

Ubhi, D.,Robertus, J.D. (登録日: 2013-06-12, 公開日: 2014-03-05, 最終更新日: 2024-04-03)

主引用文献

Ubhi, D.,Kago, G.,Monzingo, A.F.,Robertus, J.D.
Structural analysis of a fungal methionine synthase with substrates and inhibitors.
J.Mol.Biol., 426:1839-1847, 2014

PubMed Abstract: The cobalamin-independent methionine synthase from Candida albicans, known as Met6p, is a 90-kDa enzyme that consists of two (βα)8 barrels. The active site is located between the two domains and has binding sites for a zinc ion and substrates L-homocysteine and 5-methyl-tetrahydrofolate-glutamate3. Met6p catalyzes transfer of the methyl group of 5-methyl-tetrahydrofolate-glutamate3 to the L-homocysteine thiolate to generate methionine. Met6p is essential for fungal growth, and we currently pursue it as an antifungal drug design target. Here we report the binding of L-homocysteine, methionine, and several folate analogs. We show that binding of L-homocysteine or methionine results in conformational rearrangements at the amino acid binding pocket, moving the catalytic zinc into position to activate the thiol group. We also map the folate binding pocket and identify specific binding residues, like Asn126, whose mutation eliminates catalytic activity. We also report the development of a robust fluorescence-based activity assay suitable for high-throughput screening. We use this assay and an X-ray structure to characterize methotrexate as a weak inhibitor of fungal Met6p.

PubMed: 24524835
DOI: 10.1016/j.jmb.2014.02.006

実験手法

X-RAY DIFFRACTION (1.75 Å)