napA encodes the catalytic subunit, the napB gene product is a soluble dihaem c and the napC gene product is a membrane-anchored tetrahaem c-type cytochrome, napE encodes a transmembrane protein of unknown function, the napD gene product is a soluble protein which is assumed to play a role in the maturation of NapA
napA encodes the catalytic subunit, the napB gene product is a soluble dihaem c and the napC gene product is a membrane-anchored tetrahaem c-type cytochrome, napE encodes a transmembrane protein of unknown function, the napD gene product is a soluble protein which is assumed to play a role in the maturation of NapA
an asymmetric MTHFR dimer with inter-domain flexibility. The extensive linker connects and interacts with both domains, the N-terminal catalytic domain (aa 40-337) consisting of an 8alpha/8beta TIM barrel, adorned with three extra alpha-helices, and the C-terminal regulatory domain (aa 363-644) making up a fold of two five-stranded beta-sheets arranged side-by-side in the core, flanked by a number of alpha-helices
alterations in the hydrophobic interactions by 1 M urea lead to dissociation of the native tetramer, resulting in stabilization of enzymatically active holoenzyme dimers, at 3 M urea followed by unfolding of the dimers to denatured monomers along with dissociation of FAD from the enzyme subunits, alterations of the electrostatic interactions by 1.2 M NaCl lead to dissociation of the enzyme into inactive, partially denatured dimers
catalytic and regulatroy domain of the enzyme are connected by a linker sequence, domain organisation of MTHFR, structure mdoel (PDB ID 6FCX). Domain organisation of MTHFR overview