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. 2014 Nov 13;10(11):e1004715. doi: 10.1371/journal.pgen.1004715

Figure 8. In vitro DHC-1 MTBD sedimentation assay and model of dynein MTBD-tubulin dimer interaction.

Figure 8

(A) SDS-PAGE gel image stained with Coomassie blue for microtubule sedimentation using purified wild-type MTBD or MTBD(D3323K) of DHC-1. Lanes from left to right represent serial 2-fold dilution of MTBD loading, with concentrations indicated. LC, loading control. (B) Quantification (mean ± S.E.M.) of MTBD co-sedimented with microtubules. Data were averaged from three independent experiments. (C) The structure of the dynein microtubule-binding domain (MTBD) complexed with the tubulin dimer. Data from Protein Data Bank (PDB#3J1T) were processed by UCSF Chimera software. The interaction surface between the H12 of the α-tubulin and the dynein MTBD was highlighted in the bottom panel. Residues of the α-tubulin were labled in black, and those from the dynein MTBD were labeled in blue. An intramolecular salt bridge was suggested to form between E3378 and R3382 of the dynein MTBD when dynein is at some distance from the tubulin surface. Upon approaching the tubulin dimer, negative charges of the H12 of tubulin dimers were hypothesized to break the MTBD intramolecular salt bridge and foster the interaction between the MTBD and the tubulin dimer [12].