A novel α-amylase Amy03713 was screened and cloned from the starch utilization strain Vibrio alginolyticus LHF01. When heterologously expressed in Escherichia coli, Amy03713 exhibited the highest enzyme activity at 45 °C and pH 7, maintained >50 % of the enzyme activity in the range of 25-75 °C and pH 5-9, and sustained >80 % of the enzyme activity in 25 % (w/v) of NaCl solution, thus showing a wide range of adapted temperatures, pH, and salt concentrations. Halomonas bluephagenesis harboring amy03713 gene was able to directly utilize starch. With optimized amylase expression, H. bluephagenesis could produce poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB). When cultured for PHB production, recombinant H. bluephagenesis was able to grow up to a cell dry weight of 11.26 g/L, achieving a PHB titer of 6.32 g/L, which is the highest titer that has been reported for PHB production from starch in shake flasks. This study suggests that Amy03713 is an ideal amylase for PHA production using starch as the carbon source in H. bluephagenesis.
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http://dx.doi.org/10.1016/j.ijbiomac.2024.129838 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720.
Polysaccharide monooxygenase (PMO) catalysis involves the chemically difficult hydroxylation of unactivated C-H bonds in carbohydrates. The reaction requires reducing equivalents and will utilize either oxygen or hydrogen peroxide as a cosubstrate. Two key mechanistic questions are addressed here: 1) How does the enzyme regulate the timely and tightly controlled electron delivery to the mononuclear copper active site, especially when bound substrate occludes the active site? and 2) How does this electron delivery differ when utilizing oxygen or hydrogen peroxide as a cosubstrate? Using a computational approach, potential paths of electron transfer (ET) to the active site copper ion were identified in a representative AA9 family PMO from (PMO9E).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Innovative Genomics Institute, University of California, Berkeley, CA 94720.
The widespread application of genome editing to treat and cure disease requires the delivery of genome editors into the nucleus of target cells. Enveloped delivery vehicles (EDVs) are engineered virally derived particles capable of packaging and delivering CRISPR-Cas9 ribonucleoproteins (RNPs). However, the presence of lentiviral genome encapsulation and replication proteins in EDVs has obscured the underlying delivery mechanism and precluded particle optimization.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
Generative artificial intelligence (AI) models trained on natural protein sequences have been used to design functional enzymes. However, their ability to predict individual reaction steps in enzyme catalysis remains unclear, limiting the potential use of sequence information for enzyme engineering. In this study, we demonstrated that sequence information can predict the rate of the S2 step of a haloalkane dehalogenase using a generative maximum-entropy (MaxEnt) model.
View Article and Find Full Text PDFFEBS Lett
January 2025
Department of Symbiotic Science of Environment and Natural Resources, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Japan.
Carbonyl sulfide hydrolase (COSase) is a unique enzyme that exhibits high activity towards carbonyl sulfide (COS) but low carbonic anhydrase (CA) activity, despite belonging to the CA family. COSase was initially identified in a sulfur-oxidizing bacterium and later discovered in the ascomycete Trichoderma harzianum strain THIF08. The COSase from T.
View Article and Find Full Text PDFCell Rep
January 2025
Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China; Shanghai Key Laboratory of Brain Function and Restoration and Neural Regeneration, Shanghai 200040, China; Neurosurgical Institute of Fudan University, Shanghai 200040, China; Shanghai Clinical Medical Center of Neurosurgery, Shanghai 200040, China. Electronic address:
Glioblastoma (GBM) is a highly lethal malignant brain tumor with poor survival rates, and chemoresistance poses a significant challenge to the treatment of patients with GBM. Here, we show that transketolase (TKT), a metabolic enzyme in the pentose phosphate pathway (PPP), attenuates the chemotherapy sensitivity of glioma cells in a manner independent of catalytic activity. Mechanistically, chemotherapeutic drugs can facilitate the translocation of TKT protein from the cytosol into the nucleus, where TKT physically interacts with XRN2 to regulate the resolution and removal of R-loops.
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