Structural characterization and biochemical analysis of ID2, an inhibitor of DNA binding 4

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Figure 10: HLH24-82-L crystals in 0.1 M MES pH 6.5, 2.5 M Lithium Acetate grown at 18°C
(A) crystals crushed and used as stock for microseeding
(B) 1:10 dilution of seed stock
(C) 1:100 dilution of seed stock
(D) 1:1000 dilution of seed stock


Since there were numerous HLH-containing proteins in the PDB but none from
the ID family, the closest homologous structure from the PDB was chosen for use in
molecular replacement studies. Because ID2 was completed before ID3 was
deposited in the PDB, the closest homologues structure, NeuroD1, had only a 30%
identity. Hence, to prepare for the possibility that the template models were not
suitable for molecular replacement, a seleno-methionine replaced HLH24-82-L was
made (HLH24-82-L-Se-Met). The same screens were used to test for crystal growth