Structure-based self-supervised learning enables ultrafast prediction of stability changes upon mutation

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Upregulation of neuronal ER-phagy improves organismal fitness and alleviates APP toxicity

Summary: ER-phagy, a selective autophagy targeting the endoplasmic reticulum (ER) for lysosomal degradation through cargo receptors, plays a critical role in ER quality control and is linked to various diseases. However, its physiological and pathological roles remain largely unclear due to a lack of animal model studies. This study establishes Drosophila as an in vivo ER-phagy model. Starvation triggers ER-phagy across multiple fly tissues. Disturbing ER-phagy by either globally upregulating or downregulating ER-phagy receptors, Atl or Rtnl1, harms the fly. Notably, moderate upregulation of ER-phagy in fly brains by overexpressing Atl or Rtnl1 significantly attenuates age-associated neurodegenerations. Furthermore, in a Drosophila model of Alzheimer’s disease expressing human amyloid precursor protein (APP), impaired ER-phagy is observed. Enhancing ER-phagy in the APP-expressing fly brain facilitates APP degradation, significantly alleviating disease symptoms. Therefore, our findings suggest that modulating ER-phagy may offer a therapeutic strategy to treat aging and diseases associated with ER protein aggregation

Molecular dynamics investigations of structural and functional changes in Bcl-2 induced by the novel antagonist BDA-366

<p>Apoptosis is a fundamental biological phenomenon, in which anti- or proapoptotic proteins of the Bcl-2 family regulate a committed step. Overexpression of Bcl-2, the prototypical antiapoptotic protein in this family, is associated with therapy resistance in various human cancers. Accordingly, Bcl-2 inhibitors intended for cancer therapy have been developed, typically against the BH3 domain. Recent experimental evidences have shown that the antiapoptotic function of Bcl-2 is not immutable, and that BDA-366, a novel antagonist of the BH4 domain, converts Bcl-2 from a survival molecule to an inducer of cell death. In this study, the underlying mechanisms of this functional conversion were investigated by accelerated molecular dynamics simulation. Results revealed that Pro127 and Trp30 in the BH4 domain rotate to stabilize BDA-366 via π-π interactions, and trigger a series of significant conformational changes of the α3 helix. This rearrangement blocks the hydrophobic binding site (HBS) in the BH3 domain and further prevents binding of BH3-only proteins, which consequently allows the BH3-only proteins to activate the proapoptotic proteins. Analysis of binding free energy confirmed that BDA-366 cross-inhibits BH3-only proteins, implying negative cooperative effects across separate binding sites. The newly identified blocked conformation of the HBS along with the open to closed transition pathway revealed by this study advances the understanding of the Bcl-2 transition from antiapoptotic to proapoptotic function, and yielded new structural insights for novel drug design against the BH4 domain.</p> <p>Communicated by Ramaswamy H. Sarma</p> <p>The ability of the small molecule BDA-366 to convert Bcl-2 from an antiapoptotic to a proapoptotic molecule was investigated by accelerated molecular dynamics simulation. Results show that BDA-366 blocks or reduces the affinity of Bcl-2 for BH3-only proteins like Bid via negative cooperative effects, thereby releasing such proteins and unleashing their proapoptotic effects.</p

Computational redesign of a hydrolase for nearly complete PET depolymerization at industrially relevant high-solids loading

Abstract Biotechnological plastic recycling has emerged as a suitable option for addressing the pollution crisis. A major breakthrough in the biodegradation of poly(ethylene terephthalate) (PET) is achieved by using a LCC variant, which permits 90% conversion at an industrial level. Despite the achievements, its applications have been hampered by the remaining 10% of nonbiodegradable PET. Herein, we address current challenges by employing a computational strategy to engineer a hydrolase from the bacterium HR29. The redesigned variant, TurboPETase, outperforms other well-known PET hydrolases. Nearly complete depolymerization is accomplished in 8 h at a solids loading of 200 g kg−1. Kinetic and structural analysis suggest that the improved performance may be attributed to a more flexible PET-binding groove that facilitates the targeting of more specific attack sites. Collectively, our results constitute a significant advance in understanding and engineering of industrially applicable polyester hydrolases, and provide guidance for further efforts on other polymer types

Computational redesign of enzymes for regio- and enantioselective hydroamination

Introduction of innovative biocatalytic processes offers great promise for applications in green chemistry. However, owing to limited catalytic performance, the enzymes harvested from nature's biodiversity often need to be improved for their desired functions by time-consuming iterative rounds of laboratory evolution. Here we describe the use of structure-based computational enzyme design to convert Bacillus sp. YM55-1 aspartase, an enzyme with a very narrow substrate scope, to a set of complementary hydroamination biocatalysts. The redesigned enzymes catalyze asymmetric addition of ammonia to substituted acrylates, affording enantiopure aliphatic, polar and aromatic β-amino acids that are valuable building blocks for the synthesis of pharmaceuticals and bioactive compounds. Without a requirement for further optimization by laboratory evolution, the redesigned enzymes exhibit substrate tolerance up to a concentration of 300 g/L, conversion up to 99%, β-regioselectivity >99% and product enantiomeric excess >99%. The results highlight the use of computational design to rapidly adapt an enzyme to industrially viable reactions