Figure 2

Structural organization of MapZ cytoplasmic domain (residues 1-159). (a) Amino acid conservation scores as calculated by the Consurf webserver (http://consurf.tau.ac.il/)²³ are displayed on the MapZ_cyto protein sequence. Scores range from 0 (not conserved, white) to 9 (highly conserved, magenta). (b) Disorder scores predicted along the protein sequence by the IUPred software (http://iupred2a.elte.hu/)¹⁹. Highly disordered regions correspond to scores above 0.5. (c) Neighbor-corrected structural propensity (ncSP)²⁵ scores calculated from C’, C^α, and C^β NMR chemical shifts of MapZ_cyto. ncSP scores reveal the propensity to form secondary structures (zero for random coil, positive for α-helices and negative for β-sheets). The yellow band represents a cutoff value of 0.1, which outlines the absence of marked structural propensity. A helix plot representation obtained from the HELIQUEST server²⁷ is displayed for two regions (π-helix for residues 45 to 68 and α-helix for residues 79 to 95) with larger helical propensity. Positively-charged, negatively-charged, polar, and non-polar hydrophobic residues are colored in dark-blue, red, purple, and yellow, respectively. (d) Ratio of R₂/R₁ relaxation rate constant values (in red) and corresponding errors (in black) obtained at 5 °C displayed on the MapZ_cyto sequence. R₂/R₁ ratio values significantly above average are identified for regions spanning residues 45 to 68 and 79 to 95. This might suggest the presence of a transient local compactness for those two regions.