Proc Natl Acad Sci U S A
December 2024
Bacterial microcompartments (BMCs) are prokaryotic organelles that consist of a protein shell which sequesters metabolic reactions in its interior. While most of the substrates and products are relatively small and can permeate the shell, many of the encapsulated enzymes require cofactors that must be regenerated inside. We have analyzed the occurrence of an enzyme previously assigned as a cobalamin (vitamin B) reductase and, curiously, found it in many unrelated BMC types that do not employ B cofactors.
View Article and Find Full Text PDFIn response to the disruption of gas supplies from Russia following the invasion of Ukraine in 2022, European politicians and public utilities appealed to citizens and customers to conserve natural gas. Moreover, they strengthened economic incentives for gas conservation. In fact, a substantial amount of natural gas was saved during the winter of 2022/23.
View Article and Find Full Text PDFCarboxysomes are protein microcompartments found in cyanobacteria, whose shell encapsulates rubisco at the heart of carbon fixation in the Calvin cycle. Carboxysomes are thought to locally concentrate CO in the shell interior to improve rubisco efficiency through selective metabolite permeability, creating a concentrated catalytic center. However, permeability coefficients have not previously been determined for these gases, or for Calvin-cycle intermediates such as bicarbonate ([Formula: see text]), 3-phosphoglycerate, or ribulose-1,5-bisphosphate.
View Article and Find Full Text PDFStress exerted by excess captured light energy in cyanobacteria is prevented by the photoprotective activity of the orange carotenoid protein (OCP). Under high light, the OCP converts from an orange, inactive form (OCPO) into the red form (OCPR) that binds to and quenches the phycobilisome (PBS). Structurally, the OCP consists of two domains: the N-terminal effector domain and a C-terminal regulatory domain.
View Article and Find Full Text PDFAs the call for an international standard for milk from grassland-based production systems continues to grow, so too do the monitoring and evaluation policies surrounding this topic. Individual stipulations by countries and milk producers to market their milk under their own grass-fed labels include a compulsory number of grazing days per year (ranging from 120 d for certain labels to 180 d for others), a specified amount of herbage in the diet, or a prescribed dietary proportion of grassland-based forages (GBF) fed and produced on-farm. As these multifarious policy and label requirements are laborious and costly to monitor on-farm, fast economical proxies would be advantageous to verify the proportion of GBF consumed by the cows in the final product.
View Article and Find Full Text PDFBacterial microcompartments (BMCs) are protein-bound organelles found in some bacteria that encapsulate enzymes for enhanced catalytic activity. These compartments spatially sequester enzymes within semipermeable shell proteins, analogous to many membrane-bound organelles. The shell proteins assemble into multimeric tiles; hexamers, trimers, and pentamers, and these tiles self-assemble into larger assemblies with icosahedral symmetry.
View Article and Find Full Text PDFBacterial microcompartments (BMCs) are self-assembling, selectively permeable protein shells that encapsulate enzymes to enhance catalytic efficiency of segments of metabolic pathways through means of confinement. The modular nature of BMC shells' structure and assembly enables programming of shell permeability and underscores their promise in biotechnology engineering efforts for applications in industry, medicine, and clean energy. Realizing this potential requires methods for encapsulation of abiotic molecules, which have been developed here for the first time.
View Article and Find Full Text PDFBacterial microcompartments (BMCs) are prokaryotic organelles that consist of a protein shell which sequesters metabolic reactions in its interior. While most of the substrates and products are relatively small and can permeate the shell, many of the encapsulated enzymes require cofactors that must be regenerated inside. We have analyzed the occurrence of an enzyme previously assigned as a cobalamin (vitamin B) reductase and, curiously, found it in many unrelated BMC types that do not employ B cofactors.
View Article and Find Full Text PDFTrends Biochem Sci
September 2024
Cyanobacteria uniquely contain a primitive water-soluble carotenoprotein, the orange carotenoid protein (OCP). Nearly all extant cyanobacterial genomes contain genes for the OCP or its homologs, implying an evolutionary constraint for cyanobacteria to conserve its function. Genes encoding the OCP and its two constituent structural domains, the N-terminal domain, helical carotenoid proteins (HCPs), and its C-terminal domain, are found in the most basal lineages of extant cyanobacteria.
View Article and Find Full Text PDFCyanobacteria use large antenna complexes called phycobilisomes (PBSs) for light harvesting. However, intense light triggers non-photochemical quenching, where the orange carotenoid protein (OCP) binds to PBS, dissipating excess energy as heat. The mechanism of efficiently transferring energy from phycocyanobilins in PBS to canthaxanthin in OCP remains insufficiently understood.
View Article and Find Full Text PDFBacterial microcompartments (BMCs) are protein-bound organelles found in some bacteria which encapsulate enzymes for enhanced catalytic activity. These compartments spatially sequester enzymes within semi-permeable shell proteins, analogous to many membrane-bound organelles. The shell proteins assemble into multimeric tiles; hexamers, trimers, and pentamers, and these tiles self-assemble into larger assemblies with icosahedral symmetry.
View Article and Find Full Text PDFBackground/aim: Neuroblastoma is a common childhood cancer with poor survival for children with high-risk disease, and ongoing research to improve outcomes is needed. Patient-derived xenografts (PDX) and genetically engineered mouse models (GEMM) are reliable models for oncologic research; however, they are resource-intensive, expensive, and require significant expertise to develop and maintain. We developed an orthotopic xenograft murine model of neuroblastoma that utilizes cryopreserved banks of human neuroblastoma cell lines, requires minimal equipment, and is easily reproducible.
View Article and Find Full Text PDFThe orange carotenoid protein (OCP) functions as a sensor of the ambient light intensity and as a quencher of bilin excitons when it binds to the core of the cyanobacterial phycobilisome. We show herein that the photoactivation mechanism that converts the resting, orange-colored state, OCP, to the active red-colored state, OCP, requires a sequence of two reactions, each requiring absorption of a single photon by an intrinsic ketocarotenoid chromophore. Global analysis of absorption spectra recorded during continuous illumination of OCP preparations from sp.
View Article and Find Full Text PDFPhotosynthetic organisms harvest light using pigment-protein complexes. In cyanobacteria, these are water-soluble antennae known as phycobilisomes (PBSs). The light absorbed by PBS is transferred to the photosystems in the thylakoid membrane to drive photosynthesis.
View Article and Find Full Text PDFPurpose: While cancer treatment advancements have increased the number of reproductive-aged women survivors, they can harm reproductive function. Despite national guidelines, oncofertility service uptake remains low. This review explores interventions for fertility preservation alignment with American Society of Clinical Oncology (ASCO) guidelines and consideration of a multilevel framework.
View Article and Find Full Text PDFWe have discovered a new cluster of genes that is found exclusively in the Actinobacteria phylum. This locus includes genes for the 2-aminophenol -cleavage pathway and the shell proteins of a bacterial microcompartment (BMC) and has been named aromatics (ARO) for its putative role in the breakdown of aromatic compounds. In this study, we provide details about the distribution and composition of the ARO BMC locus and conduct phylogenetic, structural, and functional analyses of the first two enzymes in the catabolic pathway: a unique 2-aminophenol dioxygenase, which is exclusively found alongside BMC shell genes in Actinobacteria, and a semialdehyde dehydrogenase, which works downstream of the dioxygenase.
View Article and Find Full Text PDFJ Prim Care Community Health
July 2023
Background: The lesbian, gay, bisexual, transgender, and queer/questioning (LGBTQ) community experiences health disparities. It is thus imperative that medical trainees receive training in the care of LGBTQ community. The objective of this study was to identify gaps in knowledge and comfort among medical school students in providing care for the LGBTQ community.
View Article and Find Full Text PDFObjective: This study aimed to evaluate the relationship between peripartum mean arterial pressure (MAP) and postpartum readmission for preeclampsia with severe features.
Study Design: This is a retrospective case-control study comparing adult parturients readmitted for preeclampsia with severe features to matched nonreadmitted controls. Our primary objective was to evaluate the association between MAP at three time points during the index hospitalization (admission, 24-hour postpartum, and discharge) and readmission risk.
In a representative sample of the U.S. population during the first summer of the COVID-19 pandemic, we investigate how prosociality and ideology interact in their relationship with health-protecting behavior and trust in the government to handle the crisis.
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