Figure 2

3D-model of the N-terminus of α-DG with the myc-tag inserted in position 170. The whole N-terminal region of murine α-DG (positions 3–313 referring to the general numeration based on the human sequence), including i) the ≈ 160-180 endogenous loop region that in our 3D structure could not be solved due to its flexibility [10], and ii) an exogenous 10 a.a. myc-tag inserted between positions 170 and 171, was modeled using the widely used server I-TASSER, which allows ab initio modeling of small proteins [16]. The presence of the myc-tag (reported in yellow) does not alter the intrinsic flexibility of this region, which on the contrary remains rather disorganized. Such an insertion is therefore unlikely to influence either the secondary or the tertiary structures of the two surrounding α-DG subdomains, so that the overall folding of the whole α-DG subunit is preserved. Color code for structural elements: light blue (β-strand), red (α-helix), grey (turn or loop) and yellow (myc tag).