Peptidylglycine α-hydroxylating monooxygenase is a noninteracting bicopper enzyme that stereospecifically hydroxylates the terminal glycine of small peptides for its later amidation. Neuroendocrine messengers, such as oxytocin, rely on the biological activity of this enzyme. Each catalytic turnover requires one oxygen molecule, two protons from the solvent, and two electrons. Despite this enzyme having been widely studied, a consensus on the reaction mechanism has not yet been found. Experiments and theoretical studies favor a pro-S abstraction of a hydrogen atom followed by the rebinding of an OH group. However, several hydrogen-abstracting species have been postulated; because two protons are consumed during the reaction, several protonation states are available. An electron transfer between the copper atoms could play a crucial role for the catalysis as well. This leads to six possible abstracting species. In this study, we compare them on equal footing. We perform quantum mechanics/molecular mechanics calculations, considering the glycine hydrogen abstraction. Our results suggest that the most likely mechanism is a protonation of the abstracting species before the hydrogen abstraction and another protonation as well as a reduction before OH rebinding.
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http://dx.doi.org/10.1074/jbc.M114.558494 | DOI Listing |
Sci Rep
January 2025
College of Mechanical Engineering, Zhejiang University of Technology, No.18, Chaowang Road, Hangzhou, 310014, Zhejiang Province, China.
To observe the chemical mechanical polishing (CMP) process at the atomic scale, reactive force field molecular dynamics (ReaxFF-MD) was employed to simulate the polishing of 6 H-SiC under three conditions: dry, pure water, and HO solution. This study examined the reactants on the surface of 6 H-SiC during the reaction in the HO solution, along with the dissociation and adsorption processes of HO and water molecules. The mechanisms for atom removal during the CMP process were elucidated.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Critical Care Medicine, Tongde Hospital of Zhejiang Province, #234 Gucui Road, Hangzhou, 310012, Zhejiang, People's Republic of China.
The intestinal barrier function is a critical defense mechanism in the human body, serving as both the primary target and initiating organ in cases of sepsis. Preserving the integrity of this barrier is essential for preventing complications and diseases, including sepsis and mortality. Despite this importance, the impact of resveratrol on intestinal barrier function remains unclear.
View Article and Find Full Text PDFAnn Clin Microbiol Antimicrob
January 2025
Department of Clinical Laboratory, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.
Background: The emergence of colistin resistance in carbapenem-resistant Klebsiella pneumoniae (CRKP) is a significant public health concern, as colistin has been the last resort for treating such infections. This study aimed to investigate the prevalence and molecular characteristics of colistin-resistant CRKP isolates in Central South China.
Methods: CRKP isolates from twelve hospitals in Central South China were screened for colistin resistance using broth microdilution.
Trends Biochem Sci
January 2025
Department of Chemistry, Syracuse University, Syracuse, NY 13244, USA; Department of Biology, Syracuse University, Syracuse, NY 13244, USA; Bioinspired Institute, Syracuse University, Syracuse, NY 13244, USA; Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY 13244, USA. Electronic address:
Protein quality control (PQC) mechanisms including the ubiquitin (Ub)-proteasome system (UPS), autophagy, and chaperone-mediated refolding are essential to maintain protein homeostasis in cells. Recent studies show that these PQC mechanisms are further modulated by biomolecular condensates that sequester PQC components and compartmentalize reactions. Accumulating evidence points towards the PQC machinery playing a pivotal role in regulating the assembly, disassembly, and viscoelastic properties of several condensates.
View Article and Find Full Text PDFAm J Ophthalmol
January 2025
Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI. Electronic address:
Purpose: To summarize and categorize postulated mechanisms of immune checkpoint inhibitor (ICI)-mediated retinal and choroidal inflammation and discuss resulting implications for evaluation and management of these adverse reactions.
Design: Targeted literature review with interpretation and perspective Methods: We performed a review of selected literature describing immune-mediated retinal and choroidal adverse reactions associated with ICI therapy, synthesizing and categorizing the likely underlying pathogenic mechanisms. Based on these mechanistic categories, we provide perspective on a rational approach to the evaluation of patients with ICI-associated inflammatory disorders of the retina and choroid.
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