Chaperone Protein Inhibition

Targeted Protein Degradation (TPD) is an emerging new modality of drug discovery that offers unprecedented therapeutic benefits over traditional protein inhibition. Most importantly, TPD unlocks the untapped pool of the proteome that to date has been considered undruggable. Captor Therapeutics (Captor) is the fourth global, and first European, company that develops small molecule drug candidates based on the principles of targeted protein degradation. Captor is located in Basel, Switzerland and Wroclaw, Poland and exploits the best opportunities of the two sites – experience and non-dilutive European grants, and talent pool, respectively. Through over $38 M of funding, Captor has been active in three areas of TPD: molecular glues, bi-specific degraders and direct degraders, ObteronsTM.

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Threonine 204 of the chaperone protein Hsc70 influences the structure of the active site, but is not essential for ATP hydrolysis.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(20)80529-8 ◽

1993 ◽

Vol 268 (32) ◽

pp. 24323-24329

Author(s):

M.C. O'Brien ◽

D.B. McKay

Keyword(s):

Active Site ◽

Atp Hydrolysis ◽

Chaperone Protein

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Characterization of a novel moderate-substrate specificity amino acid racemase from the hyperthermophilic archaeon Thermococcus litoralis

Bioscience Biotechnology and Biochemistry ◽

10.1093/bbb/zbab078 ◽

2021 ◽

Author(s):

Ryushi Kawakami ◽

Chinatsu Kinoshita ◽

Tomoki Kawase ◽

Mikio Sato ◽

Junji Hayashi ◽

...

Keyword(s):

Amino Acid ◽

Substrate Specificity ◽

Enzyme Stability ◽

Hyperthermophilic Archaea ◽

Thermococcus Litoralis ◽

Hyperthermophilic Archaeon ◽

Aminobutyrate Aminotransferase ◽

Chaperone Protein ◽

Amino Acid Racemase

Abstract The amino acid sequence of the OCC_10945 gene product from the hyperthermophilic archaeon Thermococcus litoralis DSM5473, originally annotated as γ-aminobutyrate aminotransferase, is highly similar to that of the uncharacterized pyridoxal 5ʹ-phosphate (PLP)-dependent amino acid racemase from Pyrococcus horikoshii. The OCC_10945 enzyme was successfully overexpressed in Escherichia coli by co-expression with a chaperone protein. The purified enzyme demonstrated PLP-dependent amino acid racemase activity primarily toward Met and Leu. Although PLP contributed to enzyme stability, it only loosely bound to this enzyme. Enzyme activity was strongly inhibited by several metal ions, including Co2+ and Zn2+, and non-substrate amino acids such as l-Arg and l-Lys. These results suggest that the underlying PLP-binding and substrate recognition mechanisms in this enzyme are significantly different from those of the other archaeal and bacterial amino acid racemases. This is the first description of a novel PLP-dependent amino acid racemase with moderate substrate specificity in hyperthermophilic archaea.

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Mechanistic basis of breast cancer resistance protein inhibition by new indeno[1,2-b]indoles

Scientific Reports ◽

10.1038/s41598-020-79892-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Diogo Henrique Kita ◽

Nathalie Guragossian ◽

Ingrid Fatima Zattoni ◽

Vivian Rotuno Moure ◽

Fabiane Gomes de Moraes Rego ◽

...

Keyword(s):

Docking Study ◽

Indole Derivatives ◽

Cancer Resistance ◽

Protein Inhibition ◽

Atp Binding Cassette Transporter ◽

Promising Strategy ◽

Resistance Protein ◽

Mechanistic Basis ◽

Inhibition Potency ◽

New Generation

AbstractThe ATP-binding cassette transporter ABCG2 mediates the efflux of several chemotherapeutic drugs, contributing to the development of multidrug resistance (MDR) in many cancers. The most promising strategy to overcome ABCG2-mediated MDR is the use of specific inhibitors. Despite many efforts, the identification of new potent and specific ABCG2 inhibitors remains urgent. In this study, a structural optimization of indeno[1,2-b]indole was performed and a new generation of 18 compounds was synthesized and tested as ABCG2 inhibitors. Most compounds showed ABCG2 inhibition with IC50 values below 0.5 µM. The ratio between cytotoxicity (IG50) and ABCG2 inhibition potency (IC50) was used to identify the best inhibitors. In addition, it was observed that some indeno[1,2-b]indole derivatives produced complete inhibition, while others only partially inhibited the transport function of ABCG2. All indeno[1,2-b]indole derivatives are not transported by ABCG2, and even the partial inhibitors are able to fully chemosensitize cancer cells overexpressing ABCG2. The high affinity of these indeno[1,2-b]indole derivatives was confirmed by the strong stimulatory effect on ABCG2 ATPase activity. These compounds did not affect the binding of conformation-sensitive antibody 5D3 binding, but stabilized the protein structure, as revealed by the thermostabilization assay. Finally, a docking study showed the indeno[1,2-b]indole derivatives share the same binding site as the substrate estrone-3-sulfate.

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Chalcones as Promising Antitumor Agents by Targeting the p53 Pathway: An Overview and New Insights in Drug-Likeness

Molecules ◽

10.3390/molecules26123737 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3737

Author(s):

Joana Moreira ◽

Joana Almeida ◽

Lucília Saraiva ◽

Honorina Cidade ◽

Madalena Pinto

Keyword(s):

Antitumor Agents ◽

P53 Protein ◽

Cancer Therapeutics ◽

Tp53 Gene ◽

Inhibitory Effect ◽

Pharmacokinetic Parameters ◽

P53 Pathway ◽

Protein Inhibition ◽

In Silico Studies ◽

Binding Cleft

The p53 protein is one of the most important tumor suppressors that are frequently inactivated in cancer cells. This inactivation occurs either because the TP53 gene is mutated or deleted, or due to the p53 protein inhibition by endogenous negative regulators, particularly murine double minute (MDM)2. Therefore, the reestablishment of p53 activity has received great attention concerning the discovery of new cancer therapeutics. Chalcones are naturally occurring compounds widely described as potential antitumor agents through several mechanisms, including those involving the p53 pathway. The inhibitory effect of these compounds in the interaction between p53 and MDM2 has also been recognized, with this effect associated with binding to a subsite of the p53 binding cleft of MDM2. In this work, a literature review of natural and synthetic chalcones and their analogues potentially interfering with p53 pathway is presented. Moreover, in silico studies of drug-likeness of chalcones recognized as p53–MDM2 interaction inhibitors were accomplished considering molecular descriptors, biophysiochemical properties, and pharmacokinetic parameters in comparison with those from p53–MDM2 in clinical trials. With this review, we expect to guide the design of new and more effective chalcones targeting the p53 pathway.

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Epitope Mapping of Monoclonal Antibodies to Calreticulin Reveals That Charged Amino Acids Are Essential for Antibody Binding

Antibodies ◽

10.3390/antib10030031 ◽

2021 ◽

Vol 10 (3) ◽

pp. 31

Author(s):

Ann Christina Bergmann ◽

Cecilie Kyllesbech ◽

Rimantas Slibinskas ◽

Evaldas Ciplys ◽

Peter Højrup ◽

...

Keyword(s):

Amino Acids ◽

Monoclonal Antibodies ◽

Epitope Mapping ◽

Biological Function ◽

Specific Binding ◽

Enzyme Linked Immunosorbent Assay ◽

Potential Therapeutic Target ◽

Charged Amino Acids ◽

Chaperone Protein ◽

Terminal Amino

Calreticulin is a chaperone protein, which is associated with myeloproliferative diseases. In this study, we used resin-bound peptides to characterize two monoclonal antibodies (mAbs) directed to calreticulin, mAb FMC 75 and mAb 16, which both have significantly contributed to understanding the biological function of calreticulin. The antigenicity of the resin-bound peptides was determined by modified enzyme-linked immunosorbent assay. Specific binding was determined to an 8-mer epitope located in the N-terminal (amino acids 34–41) and to a 12-mer peptide located in the C-terminal (amino acids 362–373). Using truncated peptides, the epitopes were identified as TSRWIESK and DEEQRLKEEED for mAb FMC 75 and mAb 16, respectively, where, especially the charged amino acids, were found to have a central role for a stable binding. Further studies indicated that the epitope of mAb FMC 75 is assessable in the oligomeric structure of calreticulin, making this epitope a potential therapeutic target.

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