Mechanically interlocking complexes

A mechanically interlocked complex comprising a compound mechanically interlocked with a fragment antigen-binding (Fab) domain,

• said Fab domain comprising a hole within a central cavity lined by amino acid residues of the VH, VL, CH1, and CL regions of said Fab domain, wherein said central cavity comprises a non-CDR binding site;
• wherein said amino acid residues of the VL region are a threonine at position 40, an asparagine at position 41, and an aspartate at position 85, according to Kabat numbering, and
• wherein said amino acid residues of the VH region are a seine or proline at position 40 and an isoleucine, tyrosine, methionine, phenylalanine, or a tryptophan at position 89, according to Kabat numbering;
• said compound comprising a Fab binding moiety attached to a steric hindering chemical moiety through a chemical linker,
• wherein said Fab binding moiety is bound to said non-CDR binding site, said chemical linker passes through said hole, and steric hindrance occurs between said steric hindering chemical moiety and amino acids lining said hole thereby mechanically interlocking said compound and said Fab;
• wherein said compound has the formula:
• R1-L1-R2
• wherein R1 is
• R3—X0-X1-X2-X3-X4-X5-X6-X7-X8-X9-X10-X11-X12-R4
• wherein:
• X0 is Ser or null;
• X1 is Cys, Ser, Gly, β-alanine, diaminopropionic acid, β-azidoalanine, or null;
• X2 is Gln or null;
• X3 is Phe, Tyr, β,β′-diphenyl-Ala, His, Asp, 2-bromo-L-phenylalanine, 3-bromo-L-phenylalanine, 4-bromo-L-phenylalanine, Asn, Gln, a modified Phe, or a boronic acid-containing residue;
• X4 is Asp or Asn;
• X5 is Leu, β,β′-diphenyl-Ala, Phe, Trp, Tyr, tryptophan, or tyrosine, or a boronic acid-containing residue;
• X6 is Ser or Cys;
• X7 is Thr, Ser or Cys;
• X8 is an amino acid comprising a side chain of the formula -L1A-L1-R2,
• wherein L1A is substituted or unsubstituted alkylene, substituted or unsubstituted heteroalkylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted heterocycloalkylene, substituted or unsubstituted arylene or substituted or unsubstituted heteroarylene;
• wherein L1 is said chemical linker of about 5 Å to about 15 Å in length;
• and
• R2 is said steric hindering chemical moiety wherein the longest bond length distance is at least 10 Å;
• X9 is Arg or Ala;
• X10 is Leu, Gln, Glu, β,β′-diphenyl-Ala, Phe, Trp, Tyr, tryptophan, or tyrosine, or a boronic acid-containing residue;
• X11 is Lys or Arg;
• X12 is Cys, Gly, 7-aminoheptanoic acid, β-alanine, diaminopropionic acid, propargylglycine, isoaspartic acid, or null,
• R3 and R4 are independently null, -L2-R5 or an amino acid peptide sequence optionally substituted with -L2-R5, wherein L2 is a covalent or non-covalent linker and R5 is a therapeutic agent, a diagnostic agent, or a detectable agent;
• and
• wherein X1 and X12 are optionally joined together to form a cyclic peptidyl moiety.