Biochemical and structural characterization of meningococcal methylenetetrahydrofolate reductase
Issued Date
2023-06-01
Resource Type
ISSN
09618368
eISSN
1469896X
DOI
Scopus ID
2-s2.0-85160870095
Pubmed ID
37165541
Journal Title
Protein Science
Volume
32
Issue
6
Rights Holder(s)
SCOPUS
Bibliographic Citation
Protein Science Vol.32 No.6 (2023)
Suggested Citation
Pantong W., Pederick J.L., Maenpuen S., Tinikul R., Jayapalan J.J., Jovcevski B., Wegener K.L., Bruning J.B., Salaemae W. Biochemical and structural characterization of meningococcal methylenetetrahydrofolate reductase. Protein Science Vol.32 No.6 (2023). doi:10.1002/pro.4654 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/83035
Title
Biochemical and structural characterization of meningococcal methylenetetrahydrofolate reductase
Other Contributor(s)
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is a key metabolic enzyme in colonization and virulence of Neisseria meningitidis, a causative agent of meningococcal diseases. Here, the biochemical and structural properties of MTHFR from a virulent strain of N. meningitidis serogroup B (NmMTHFR) were characterized. Unlike other orthologs, NmMTHFR functions as a unique homohexamer, composed of three homo-dimerization partners, as shown in our 2.7 Å resolution crystal structure. Six active sites were formed solely within monomers and located away from the oligomerization interfaces. Flavin adenine dinucleotide cofactor formed hydrogen bonds with conserved sidechains, positioning its isoalloxazine ring adjacent to the overlapping binding sites of nicotinamide adenine dinucleotide (NADH) coenzyme and CH2-H4folate substrate. NmMTHFR utilized NADH (Km = 44 μM) as an electron donor in the NAD(P)H-CH2-H4folate oxidoreductase assay, but not nicotinamide adenine dinucleotide phosphate (NADPH) which is the donor required in human MTHFR. In silico analysis and mutagenesis studies highlighted the significant difference in orientation of helix α7A (Phe215–Thr225) with that in the human enzyme. The extended sidechain of Met221 on helix α7A plays a role in stabilizing the folded structure of NADH in the hydrophobic box. This supports the NADH specificity by restricting the phosphate group of NADPH that causes steric clashes with Glu26. The movement of Met221 sidechain allows the CH2-H4folate substrate to bind. The unique topology of its NADH and CH2-H4folate binding pockets makes NmMTHFR a promising drug target for the development of new antimicrobial agents that may possess reduced off-target side effects.