7VG5

Structural insight into a molecular mechanism of methenyltetrahydrofolate cyclohydrolase from Methylobacterium extorquens AM1.

(2022) Int J Biol Macromol 202: 234-240

• PubMed: 35051495 Search on PubMed
• DOI: https://doi.org/10.1016/j.ijbiomac.2022.01.072
• Primary Citation of Related Structures:  
  7VG4, 7VG5


• PubMed Abstract: 
  

  Bioconversion of the C1 compounds into value-added products is one of the CO ₂ -reducing strategies. In particular, because CO ₂ can be easily converted into formate, the efficient and direct bioconversion of CO ₂ through formate assimilation is attracting attention. The tetrahydrofolate (THF) cycle is the highly efficient reconstructed formate assimilation pathway, and 5,10-methenyltetrahydrofolate cyclohydrolase (FchA) is an essential enzyme involved in the THF cycle. In this study, a kinetic analysis of FchA from Methylobacterium extorquens AM1 (MeFchA) was performed and revealed that the enzyme has much higher cyclization than hydrolyzation activity, making it an optimal enzyme for formate assimilation. The crystal structure of MeFchA in the apo- and the THF-complexed forms was also determined, revealing that the substrate-binding site of the enzyme has three differently charged regions to stabilize the three differently charged moieties of the formyl-THF substrate. The residues involved in the substrate binding were also verified through site-directed mutagenesis. This study provides a biochemical and structural basis for the molecular mechanism underlying formate assimilation.

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Organizational Affiliation: 

School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu, 41566, Republic of Korea.