Assembly and Application of a Low Budget Photo Reactor

Photochemistry is a fast growing research field and many transformations previously not accessible to chemists now have become part of an ever growing standard repertoire. The limiting factors for a photo reactor system however is the possibility to perform stirring, removal of excess heat and the irradiation with UV or visible light – all that within a secure surrounding. Systems for starters may be as expensive as several thousand Euro. Here we design and assemble a LED photo reactor using scrap and standard materials, only spending less than 30 € for a LED. The system may be adjusted to any required wave length and its assembly is shown for the use of a 400 nm wave length lamp. To demonstrate its application, we then exemplarily use the reactor in the removal of a photo labile protection group during the synthesis of a SARS-CoV-2 spike protein glyco peptide.<br /

Optimization of N-piperidinyl-benzimidazolone derivatives as potent and selective inhibitors of 8-Oxo Guanine DNA Glycosylase 1

8-oxo Guanine DNA Glycosylase 1 is the initiating enzyme within base excision repair and removes oxidized guanines from damaged DNA. Since unrepaired 8-oxoG could lead to G:C→T:A transversion, base removal is of the utmost importance for cells to ensure genomic integrity. For cells with elevat-ed levels of reactive oxygen species this dependency is further increased. In the past we and others have validated OGG1 as a target for inhibitors to treat cancer and inflammation. Here, we present the optimization campaign that led to the broadly used tool compound TH5487. Based on a high-throughput screen, we performed hit to lead expansion and arrived at potent and selective substituted N-piperidinyl-benzimidazolones. Using X-ray crystallography data, we describe the surprising bind-ing mode of the most potent member of the class, TH8535. Here, the N-Piperidinyl-linker adopts a chair instead of a boat conformation which was found for weaker analogues. We further demonstrate cellular target engagement and efficacy of TH8535 against a number of cancer cell lines

Optimization of N-Piperidinyl-Benzimidazolone Derivatives as Potent and Selective Inhibitors of 8-Oxo-Guanine DNA Glycosylase 1

8-oxo Guanine DNA Glycosylase 1 is the initiating enzyme within base excision repair and removes oxidized guanines from damaged DNA. Since unrepaired 8-oxoG could lead to G : C→T : A transversion, base removal is of utmost importance for cells to ensure genomic integrity. For cells with elevated levels of reactive oxygen species this dependency is further increased. In the past we and others have validated OGG1 as a target for inhibitors to treat cancer and inflammation. Here, we present the optimization campaign that led to the broadly used tool compound TH5487. Based on results from a small molecule screening campaign, we performed hit to lead expansion and arrived at potent and selective substituted N-piperidinyl-benzimidazolones. Using X-ray crystallography data, we describe the surprising binding mode of the most potent member of the class, TH8535. Here, the N-Piperidinyl-linker adopts a chair instead of a boat conformation which was found for weaker analogues. We further demonstrate cellular target engagement and efficacy of TH8535 against a number of cancer cell lines

Small-molecule activation of OGG1 increases oxidative DNA damage repair by gaining a new function

Oxidative DNA damage is recognised by 8-oxoguanine (8-oxoG) DNA glycosylase 1 (OGG1), which excises 8-oxoG, leaving a substrate for apurinic endonuclease 1 (APE1), initiating repair. Here, we describe a small molecule (TH10785) that interacts with the Phe319 and Gly42 amino acids of OGG1, increases the enzyme activity 10-fold and generates a novel β,δ-lyase enzymatic function. TH10785 controls the catalytic activity mediated by a nitrogen base within its molecular structure. In cells, TH10785 increases OGG1 recruitment to and repair of oxidative DNA damage. This alters the repair process, which no longer requires APE1 but instead is dependent on polynucleotide kinase phosphatase (PNKP1) activity. The increased repair of oxidative DNA lesions with a small molecule may have therapeutic applications in various diseases and ageing.European Research Council TAROX-695376Swedish Research Council 2015-00162 and 2018-03406Ministry of Science and Innovation, Spain/State Research Agency, Spain/10.13039/501.100011033European Regional Development Fund (ERDF) BFU2017-83900-PCrafoord Foundation 20190532Alfred Osterlund FoundationSwedish Pain Relief FoundationSwedish Cancer Society CAN 2018/0658 and CAN 2017/716Torsten and Ragnar Soderberg foundationDr. Ake-Olsson Foundation for Hematological Research 2020-00306Thomas Helleday Foundation for medical research postdoctoral stipendsNTNU Enabling Technology Programme on BiotechnologyEMBO Short-Term Fellowship 9005FEBS Short-Term FellowshipScandinavian ExchangeGerman Research Foundation (DFG) 239748522Sonderforschungsbereich (SFB) 1127Leibniz AwardNorwegian Research Council 303369Karolinska Institutet Research Foundation 2020-02186Lars Hiertas Minne StiftelseAsociacion Espanola Contra Cancer grant Postdoctoral AECC 2020 POSTD20042BENIInstituto de Salud Carlos III CP19/00063, PI20/00329 and PI19/00640European Social Fund (ESF)Innovative Medicines Initiative 2 Joint Undertaking (JU) 875510European Union's Horizon 2020 research and innovation program, Marie Sklodowska-Curie 722729Accepte

Nucleobase catalysts for the enzymatic activation of 8-oxoguanine DNA glycosylase 1

: Bifunctional DNA glycosylases employ an active site lysine or the N-terminus to form a Schiff base with the abasic site (AP site) base excision repair (BER) intermediate. Cleaving this reversible structure is the rate-determining step in the initiation of 8-oxoguanine (8-oxoG) repair for 8-oxoguanine DNA glycosylase 1 (OGG1). The OGG1 AP lyase activity can be increased using small molecule binders, called organocatalytic switches, to cleave the DNA backbone in a similar manner as a bifunctional DNA glycosylase. In search for novel organocatalytic switches we here identify 8-Substituted 6 thioguanines and 6-amino-pyrazolo-[3,4-d]-pyrimidine derivatives as potent and selective scaffolds enabling OGG1 to cleave AP sites opposite any canonical nucleobase by β-elimination, shaping a complete, artificial AP-lyase function. These new tool compounds enhance the cellular repair of 8-oxoG and AP sites, activating a rudimentary but canonical enzymatic activity