Figure 1. Preparatory steps for DCP.

Here, an Interaction Frame (IF) is selected for CDR-L1 and the corresponding IF sequences are synthesised for each one of the four clusters of the given length. For computational reasons the same IF is defined for all lengths of any given CDR (here, CDR-L1 for illustration purposes). Therefore, observed gaps in IF sequences correspond to insertions populated in longer lengths than the one shown in the illustrated example—gaps are filled accordingly in those lengths’ IF sequences. Spare gaps, on the other hand, may correspond to IF positions pointing to unpopulated insertions from other CDRs or deletions in the Fv sequence. Also, gaps are present if there is no Light or Heavy chain in that particular structure. Positions at the end of the IF, marked as ‘n−x’, refer to CDR-H3 positions at a sequential distance x from the last residue n (H102; see text).