biostudies-literatureKhong QTIntramural NIH HHSNational Cancer InstituteNCI NIH HHS9468-9472https://www.ebi.ac.uk/biostudies/studies/S-EPMC10681237biostudies-literatureUnknown24(51)A new dimeric alkaloid plakoramine A [(±)-1] was identified from a marine sponge Plakortis sp. Chiral-phase HPLC separation of (±)-1 led to the purified enantiomers (+)-1 and (-)-1 which both potently inhibited CBL-B E3 ubiquitin ligase activities. The absolute configurations of the enantiomers were determined by quantum chemical calculations. Scrutinization of the purification conditions revealed a previously undescribed, nonenzymatic route to form (±)-1 via photochemical conversion of its naturally occurring monomeric counterpart, plakinidine B (2).Organic lettersPhotochemical Dimerization of Plakinidine B Leads to Potent Inhibition of the E3 Ubiquitin-Protein Ligase CBL-B.PMC10681237HHSN261200800001EZIA BC011854ZIA BC011568ZIA BC011564Grkovic TLi DGoncharova EIWamiru ADalilian MSmith EARanguelova KWilson BAPLipkowitz SO'Keefe BRDu LSchnermann MJKhong QTVoeller DfalsePhotochemical Dimerization of Plakinidine B Leads to Potent Inhibition of the E3 Ubiquitin-Protein Ligase CBL-B.A new dimeric alkaloid plakoramine A [(±)-1] was identified from a marine sponge Plakortis sp. Chiral-phase HPLC separation of (±)-1 led to the purified enantiomers (+)-1 and (-)-1 which both potently inhibited CBL-B E3 ubiquitin ligase activities. The absolute configurations of the enantiomers were determined by quantum chemical calculations. Scrutinization of the purification conditions revealed a previously undescribed, nonenzymatic route to form (±)-1 via photochemical conversion of its naturally occurring monomeric counterpart, plakinidine B (2).2022-01-01T00:00:00Z2022 Dec2025-04-21T18:18:43.036Z2025-04-05T17:11:43.726ZS-EPMC106812373651699410.1021/acs.orglett.2c03922