Efficient Site‐Specific Antibody–Drug Conjugation by Engineering a Nature‐Derived Recognition Tag for Microbial Transglutaminase

Abstract

Microbial transglutaminase (mTG) has recently emerged as a powerful tool for antibody engineering. In nature, it catalyzes the formation of amide bonds between glutamine side chains and primary amines. Being applied to numerous research fields from material sciences to medicine, mTG enables efficient site‐specific conjugation of molecular architectures that possess suitable recognition motifs. In monoclonal antibodies, the lack of native transamidation sites is bypassed by incorporating specific peptide recognition sequences. Herein, we report a rapid and efficient mTG‐catalyzed bioconjugation that relies on a novel recognition motif derived from its native substrate Streptomyces papain inhibitor (SPIP). Improved reaction kinetics compared to commonly applied sequences were demonstrated for model peptides and for biotinylation of Her2‐targeting antibody trastuzumab variants. Moreover, an antibody–drug conjugate assembled from trastuzumab that was C‐terminally tagged with the novel recognition sequence revealed a higher payload‐antibody ratio than the reference antibody.

Site-selective modification strategies in antibody–drug conjugates

“…19C). 289 An analysis of the substrate preference of mTG within a series of synthetic peptides derived from sequences within the papain inhibitor, as well as DAIP, was conducted. Anti-HER2 ADCs were assembled via recognition tags fused to the heavy chain C-termini, attachment with amino-PEG 2 -BCN linkers, followed by SPAAC with the azido-PEG 3 -Val-Cit-PABC-MMAE payload.…”

An Efficient Conjugation Approach for Coupling Drugs to Native Antibodies via the PtIILinkerLxfor Improved Manufacturability of Antibody–Drug Conjugates

“…[4] The site-specific conjugation [5] was clearly a major trend during the last years; nevertheless, a recent publication showed that heterogeneous stochastic conjugation can be beneficial over homogeneous site-specific conjugation. [5a] However, even modern site-specific conjugation procedures using, for example, genetically engineered amino acids or enzymatic approaches [6] mainly focus on the efficacy of the resulting ADCs or improvement of their pharmacokinetics/pharmacodynamics. Surprisingly, little attention is paid to the overall conjugation efficiency and manufacturability of the developed procedures.…”

DNAzymes for amine and peptide lysine acylation

“…25,26 One such reaction is lysine (Lys) acylation, where Lys acetylation is critical for histones and in other contexts, [27][28][29][30] and many longer-chain Lys acylation PTMs [31][32][33] such as malonylation, 34,35 succinylation, 34,36 and glutarylation 37,38 have been discovered yet are poorly understood. 39 As an alternative to approaches that include introduction of Lys analogues, [40][41][42][43] nonsense codon suppression, [44][45][46][47][48][49] bottom-up ligation-based assembly strategies, [50][51][52] or enzymatic methods that typically require creation of a non-native protein by insertion of a specific target sequence, [53][54][55][56][57][58] DNAzymes are promising for top-down introduction of Lys acylation PTMs onto intact native proteins, [59][60][61][62][63][64][65] but only if DNAzymes can be identified with the fundamental catalytic ability of Lys acylation.…”