Allyl sulfones as efficient disulfide rebridging agents for site-specific protein modifications with up to two additional functionalities in water.

The development of a synthetic code that enables a sequence programmable feature like DNA represents a key aspect toward intelligent molecular systems. We developed herein the well-known dynamic covalent interaction between boronic acids (BAs) and catechols (CAs) into synthetic nucleobase analogs. Along a defined peptide backbone, BA or CA residues are arranged to enable sequence recognition to their complementary strand. Dynamic strand displacement and errors were elucidated thermodynamically to show that sequences are able to specifically select their partners. Unlike DNA, the pH dependency of BA/CA binding enables the dehybridization of complementary strands at pH 5.0. In addition, we demonstrate the sequence recognition at the macromolecular level by conjugating the cytochrome c protein to a complementary polyethylene glycol chain in a site-directed fashion.

A facile chemical approach integrating supramolecular chemistry, site‐selective protein chemistry, and molecular biology is described to engineer synthetic multidomain protein therapeutics that sensitize cancer cells selectively to significantly enhance antitumor efficacy of existing chemotherapeutics. The desired bioactive entities are assembled via supramolecular interactions at the nanoscale into structurally ordered multiprotein complexes comprising a) multiple copies of the chemically modified cyclic peptide hormone somatostatin for selective targeting and internalization into human A549 lung cancer cells expressing SST‐2 receptors and b) a new cysteine mutant of the C3bot1 (C3) enzyme from Clostridium botulinum, a Rho protein inhibitor that affects and influences intracellular Rho‐mediated processes like endothelial cell migration and blood vessel formation. The multidomain protein complex, SST3‐Avi‐C3, retargets C3 enzyme into non‐small cell lung A549 cancer cells and exhibits exceptional tumor inhibition at a concentration ≈100‐fold lower than the clinically approved antibody bevacizumab (Avastin) in vivo. Notably, SST3‐Avi‐C3 increases tumor sensitivity to a conventional chemotherapeutic (doxorubicin) in vivo. These findings show that the integrated approach holds vast promise to expand the current repertoire of multidomain protein complexes and can pave the way to important new developments in the area of targeted and combination cancer therapy.

The attachment of two different functionalities in a site-selective fashion represents a great challenge in protein chemistry. We report site specific dual functionalizations of peptides and proteins capitalizing on reactivity differences of cysteines in their free (thiol) and protected, oxidized (disulfide) forms. The dual functionalization of interleukin 2 and EYFP proceeded with no loss of bioactivity in a stepwise fashion applying maleimide and disulfide rebridging allyl-sulfone groups. In order to ensure broader applicability of the functionalization strategy, a novel, short peptide sequence that introduces a disulfide bridge was designed and site-selective dual labeling in the presence of biogenic groups was successfully demonstrated.

Bulk acyclic diene metathesis (ADMET) polymerization performed in the melt at temperatures up to 175 °C is completed using a cyclic (alkyl)(amino) carbene (CAAC) ruthenium‐based Grubbs catalyst. High temperature stability is investigated at temperatures well above conventional ADMET chemistry, leading to the highest weight‐average molecular weights ever achieved for any ADMET polymer. A study of isomerization tendency (double bond migration) is done via self‐metathesis of a small molecule model compound using CAAC catalysts. Minimal olefin isomerization is observed using appropriate catalyst ratios and temperatures.

Protein-based polymeric polyelectrolytes are emerging as alternative synthetic nanoparticles owing to their biodegradability and biocompatibility. However, potential in vivo toxicity remains a significant challenge. Herein an array of protein polyelectrolytes generated from cationic human serum albumin (cHSA) and polyethylene glycol (PEG) are synthesized via synthetic customization as antimicrobials for the treatment of systemic infections. By varying PEG molecular weight and chain length, in vitro hemolytic activity can be fine-tuned without significantly affecting antimicrobial potency. The optimal hybrid material, PEG (2000) -cHSA, with potent antimicrobial character, low hemolytic activity, and in vitro biofilm disruptive properties is identified. Surface plasmon resonance (SPR) evaluation demonstrates significantly higher binding activity of the protein nanoparticles to bacteria cell wall components and microfluidic live-cell imaging indicates that the nanoparticles act through a membranolytic mechanism. Given their low susceptibility to drug resistance and potent activity against resistant bacteria strains, these findings establish the PEGylated albumin nanoparticles as a potent weaponry against drug resistance and biofilm-related infection.

Peptide–polymer conjugates have been regarded as primary stronghold in biohybrid nanomedicine, which has seen extensive development due to its intrinsic property to provide complementary functions of both the peptide material and the synthetic polymer platform. Here we present an advanced macromolecular therapeutic that targets two exclusive classes of important diseases (namely, the HIV and cancer) that are implicated by extremely different causative agents. Using a facile thiol-reactive monomer, the eventual polymer facilitates multivalent conjugation of an endogenous peptide WSC02 that targets the CXCR4 chemokine receptor. The biohybrid material demonstrated both potent antiviral effects against HIV-1 as well as inhibiting cancer stem cell migration thus establishing the foundation for multimodal nanotherapeutics that simultaneously target more than one class of disease implications.

Front Cover: A series of albumin nanoparticles with antimicrobial and anti‐biofilm activities are prepared from cationic human serum albumin and polyethylene glycol (PEG). Modulation of surface charges with PEG results in reduced haemolytic activity and thereby improved hemocompatibility. This is reported by Sybil Obuobi, Ying Wang, Jasmeet Singh Khara, Andreas Riegger, Seah Ling Kuan, Pui Lai Rachel Ee in article number https://doi.org/10.1002/mabi.201800196.