Figure 3: FANCM-F binds to (MHF1–MHF2)2 tetramer.
From: The structure of the FANCM–MHF complex reveals physical features for functional assembly
(a) Ribbon representation of the overall structure of MHF–FANCM-F complex, with FANCM-F in magenta. The dimer associating with the N-terminal part of FANCM-F is labelled as MHF and the other one, interacting with the FANCM-F C terminus, is labelled as MHF′. (b) The extended structure of FANCM-F. (c) Representative experimental electron density map. Electron density map at 2.64 Å resolution contoured at 1.0 σ. The portion of FANCM-F residues 753–86 is shown. (d) The B-factor distribution of FANCM-M. The wider the tubing is, the higher the B-factor. The missing residues 730–50 are modelled in magenta circles. (e) The N-terminal 'V' segment wraps around the MHF1 α1 and α2 helices. Close-up view indicates the complementary hydrophobic interface between FANCM-F αA and MHF1 α1 helix. The involved residues are labelled in black, red and blue letters for FANCM-F, MHF1 and MHF2, respectively. (f) The C-terminal 'V' segment surrounds the same region of MHF1′ as in e. (g) The β2 strand forms five hydrogen bonds with β1. The black arcuate line indicates the trajectory of FANCM-F. (h) FANCM-F αB helix packs against α3/α3′ of MHF2/MHF2′. (i) The coil covers the surface area of partial α2′ and α3′ of MHF2′. Residues shown in sticks all make contacts with MHF2. Val749 highlighted in cyan stick inserts its side chain into the MHF2 hydrophobic core. (j) The coil following α1 extends to Gln714. FANCM-F Phe710 interacts with the MHF2 hydrophobic core with the aromatic ring. (k) The linker coil interacts with the bottom parts of MHF2 α3, viewed from the bottom in (i). (l) Structure comparison of the two (MHF1–MHF2)2 tetramers. MHF1 and MHF2 from the MHF complex are shown in orange and deep teal, respectively; those from the FANCM-F bound are shown green (MHF1) and yellow (MHF2), respectively. The line and the boxes indicate the region where difference occurs.
