Fig. 4.

Atg29 is an intrinsically disordered protein. (A) Tendency for intrinsic disorder and probability of an Atg29 residue being in a disordered binding region, as predicted by IUPred and ANCHOR, respectively. Gray areas, generated by ANCHOR, identify the disordered binding segments in Atg29 that are likely to be stabilized through binding to a globular protein partner. The Met residue at the Atg29 N terminus was not included in the calculations for this plot and the plots in B and Fig. S1B. (B) Compositional profiling of Atg29. The gray and black bars show the fractional difference [calculated as (C_X − C_PDB25)/C_PDB25] in amino acid composition of Atg29 and IDPs from the DisProt database, respectively, relative to a reference set of proteins in PDB (31) that is biased toward the composition of proteins responsive to crystallization. C_X is the content of amino acids in Atg29 or IDPs in DisProt and C_PDB25 is the corresponding value for proteins in the PDB protein set. A negative/positive fractional difference indicates depletion/enrichment in the corresponding amino acid. Amino acids are arranged on the x axis from the most rigid to the most flexible according to the Vihinen’s flexibility scale (48). (C) Migration of Atg29 fusion proteins following SDS/PAGE. (Left) Atg29 fused to the MOCR solubilization tag was visualized by immunoblotting the E. coli cell lysate with antiserum to polyHis. (Right) Atg29 fused to protein A was detected by immunoblotting the yeast cell extract with antiserum that detects PA.