Figure 1.

The general OB-fold topology. The β-strands were labeled as B1 to B5. The loops were labeled as RT, n-src, distal and omega. The N- and C-termini were labeled. Note the N-terminal starts with strand B2 and strand B1 was between omega helix and RT-loop. RT-loop was connecting B1 with B5 (see the difference with SH3-fold in Fig. 2). Note the other striking difference between the two folds, the omega helix which was present on majority of OB-fold proteins. This figure was made with bobscript [31] and rendered with povray (http://www.povray.org/).