Small molecules inducing protein degradation are important pharmacological tools to interrogate complex biology and are rapidly translating into clinical agents. However, to fully realise the ...potential of these molecules, selectivity remains a limiting challenge. Herein, we addressed the issue of selectivity in the design of CRL4CRBN recruiting PROteolysis TArgeting Chimeras (PROTACs). Thalidomide derivatives used to generate CRL4CRBN recruiting PROTACs have well described intrinsic monovalent degradation profiles by inducing the recruitment of neo‐substrates, such as GSPT1, Ikaros and Aiolos. We leveraged structural insights from known CRL4CRBN neo‐substrates to attenuate and indeed remove this monovalent degradation function in well‐known CRL4CRBN molecular glues degraders, namely CC‐885 and Pomalidomide. We then applied these design principles on a previously published BRD9 PROTAC (dBRD9‐A) and generated an analogue with improved selectivity profile. Finally, we implemented a computational modelling pipeline to show that our degron blocking design does not impact PROTAC‐induced ternary complex formation. We believe that the tools and principles presented in this work will be valuable to support the development of targeted protein degradation.
The opium poppy, Papaver somniferum, has been a source of medicinal alkaloids since the earliest civilizations, ca. 3400 B.C. The benzylisoquinoline alkaloid noscapine is produced commercially in P. ...somniferum for use as a cough suppressant, and it also has potential as an anticancer compound. The first committed step in the recently elucidated noscapine biosynthetic pathway involves the conversion of scoulerine to tetrahydrocolumbamine by 9-O-methylation, catalyzed by O-methyltransferase 1 (PSMT1). We demonstrate, through protein structures (obtained through rational crystal engineering at resolutions from 1.5 to 1.2 Å for the engineered variants) across the reaction coordinate, how domain closure allows specific methyl transfer to generate the product. SAM-dependent methyl transfer is central to myriad natural products in plants; analysis of amino acid sequence, now taking the three-dimensional structure of PSMT1 and low identity homologues into account, begins to shed light on the structural features that govern substrate specificity in these key, ubiquitous, plant enzymes. We propose how “gatekeeper” residues can determine acceptor regiochemistry, thus allowing prediction across the wide genomic resource.
Small molecules inducing protein degradation are important pharmacological tools to interrogate complex biology and are rapidly translating into clinical agents. However, to fully realise the ...potential of these molecules, selectivity remains a limiting challenge. Herein, we addressed the issue of selectivity in the design of CRL4
recruiting PROteolysis TArgeting Chimeras (PROTACs). Thalidomide derivatives used to generate CRL4
recruiting PROTACs have well described intrinsic monovalent degradation profiles by inducing the recruitment of neo-substrates, such as GSPT1, Ikaros and Aiolos. We leveraged structural insights from known CRL4
neo-substrates to attenuate and indeed remove this monovalent degradation function in well-known CRL4
molecular glues degraders, namely CC-885 and Pomalidomide. We then applied these design principles on a previously published BRD9 PROTAC (dBRD9-A) and generated an analogue with improved selectivity profile. Finally, we implemented a computational modelling pipeline to show that our degron blocking design does not impact PROTAC-induced ternary complex formation. We believe that the tools and principles presented in this work will be valuable to support the development of targeted protein degradation.
E3 ligase mediated targeted protein degradation is an ever more important area in drug discovery. In the case of cereblon two avenues exist; either heterobifunctional PROTACs, or discrete cereblon ...ligands that induce a specific neosubstrate degron association to the complex. Here we present a degron blocking approach, whereby structural and in silico understandings of degron association has directed ligand design to block IMiD‐like binding of degron containing neosubstrates, thus enhancing PROTAC selectivity. More information can be found in the Research Article by H. Bouguenina, J. J. Caldwell et al.
Noscapine is a major alkaloid that is found, along with the more commonly known drugs morphine and codeine, in the latex of opium poppy (Papaver somniferum). Noscapine has classically been used as a ...cough suppressant, but also has emerging antitumor properties. Unlike morphine and codeine, noscapine has no addictive properties. Recently, a 10-gene cluster for the synthesis of noscapine was discovered. The first distinct step in this pathway is an O-methylation of scoulerine to tetrahydrocolumbamine by a class I S-adenosylmethionine (SAM) dependent methyltransferase, referred to as Papaver somniferum O-methyltransferase 1 (PSMT1). PSMT1 is therefore an interesting target for detailed structural and functional analysis. PSMT1 has been expressed as a fusion protein, tagged to improve solubility, and purified for X-ray diffraction studies. Here we present the structures of an "apo" enzyme and an enzyme complex with SAM, bound in "open" enzyme conformations. A surface entropy reduction mutant enzyme allowed access to a closed conformation high-resolution structure in complex with S-adenosylhomocysteine (SAH) and the product tetrahydrocolumbamine. These X-ray structures provide deep insight into the structure function relationships of PSMT1. PSMT1 is a homodimer with distinct dimerisation, SAM binding and substrate binding domains. PSMT1 undergoes an inward rotation of approximately 10 degrees of the SAM binding domain upon substrate binding. This results in an 8 Å closure of the active site cleft. The acceptor substrate binds in a hydrophobic cleft, held in place by two hydrogen bonds via the hydroxyl groups at positions 2 and 9 of scoulerine. Further analysis of the plant O-methyltransferase catalytic dyad has been carried out by site-directed mutagenesis and X-ray diffraction studies. Subunit cooperativity has also been investigated with the proposal of two regulatory features. Here I present one of the highest resolution closed conformation structure of a plant O-methyltransferase to date. This provides the template for our understanding of, and future engineering substrate specificity in plant methyltransferases; an important class of enzymes in secondary metabolism.
What is mild stimulation? Merviel, P; Lourdel, E; Cabry, R ...
Gynécologie, obstétrique & fertilité
40, Številka:
9
Journal Article
Mild stimulation is the administration of low doses (150 IU/day) of FSH, continuously, from the fifth day of the cycle, associated with the administration of GnRH antagonists. Despite the lower ...number of oocytes collected during mild stimulation, they are better for pregnancy rates on with an endometrium nearest closer to the natural cycle, and reducing the risk of ovarian hyperstimulation. Although the number of IVF ± ICSI attempts is limited to 4 in France, the Mild stimulation may be proposed in young women, those with a polycystic ovary syndrome or "low responder" women.
Qu’est-ce que la mild stimulation ? Merviel, P.; Lourdel, E.; Cabry, R. ...
Gynécologie obstétrique & fertilité,
September 2012, Letnik:
40, Številka:
9
Journal Article, Conference Proceeding
La mild stimulation est l’administration de faibles doses (150UI/j) de FSH, en continu, à partir du 5e jour du cycle, associée à l’administration d’antagonistes de la GnRH. Bien que recueillis en ...plus faible nombre en mild stimulation, les ovocytes sont de meilleure qualité permettant des taux de grossesse corrects sur un endomètre plus proche du cycle naturel, en diminuant le risque d’hyperstimulation ovarienne. Même si le nombre de tentatives de FIV±ICSI est limité à 4 en France, la mild stimulation peut être proposée chez les femmes jeunes, celles ayant un syndrôme des ovaires micro-polykystiques ou chez les femmes « faibles répondeuses ».
Mild stimulation is the administration of low doses (150IU/day) of FSH, continuously, from the fifth day of the cycle, associated with the administration of GnRH antagonists. Despite the lower number of oocytes collected during mild stimulation, they are better for pregnancy rates on with an endometrium nearest closer to the natural cycle, and reducing the risk of ovarian hyperstimulation. Although the number of IVF±ICSI attempts is limited to 4 in France, the Mild stimulation may be proposed in young women, those with a polycystic ovary syndrome or “low responder” women.
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