QCs (glutaminyl cyclases; glutaminyl-peptide cyclotransferases, EC 2.3.2.5) catalyse N-terminal pyroglutamate formation in numerous bioactive peptides and proteins. The enzymes were reported to be involved in several pathological conditions such as amyloidotic disease, osteoporosis, rheumatoid arthritis and melanoma. The crystal structure of human QC revealed an unusual H-bond (hydrogen-bond) network in the active site, formed by several highly conserved residues (Ser(160), Glu(201), Asp(248), Asp(305) and His(319)), within which Glu(201) and Asp(248) were found to bind to substrate. In the present study we combined steady-state enzyme kinetic and X-ray structural analyses of 11 single-mutation human QCs to investigate the roles of the H-bond network in catalysis. Our results showed that disrupting one or both of the central H-bonds, i.e., Glu(201)...Asp(305) and Asp(248)...Asp(305), reduced the steady-state catalysis dramatically. The roles of these two COOH...COOH bonds on catalysis could be partly replaced by COOH...water bonds, but not by COOH...CONH(2) bonds, reminiscent of the low-barrier Asp...Asp H-bond in the active site of pepsin-like aspartic peptidases. Mutations on Asp(305), a residue located at the centre of the H-bond network, raised the K(m) value of the enzyme by 4.4-19-fold, but decreased the k(cat) value by 79-2842-fold, indicating that Asp(305) primarily plays a catalytic role. In addition, results from mutational studies on Ser(160) and His(319) suggest that these two residues might help to stabilize the conformations of Asp(248) and Asp(305) respectively. These data allow us to propose an essential proton transfer between Glu(201), Asp(305) and Asp(248) during the catalysis by animal QCs.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1042/BJ20071073 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Probing the Electric Double-Layer Capacitance to Understand the Reaction Environment in Conditions of Electrochemical Amination of Acetone.
ACS Appl Mater Interfaces
January 2025
Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California 90095, United States.
To elucidate interfacial dynamics during electrocatalytic reactions, it is crucial to understand the adsorption behavior of organic molecules on catalytic electrodes within the electric double layer (EDL). However, the EDL structure in aqueous environments remains intricate when it comes to the electrochemical amination of acetone, using methylamine as a nitrogen source. Specifically, the interactions of acetone and methylamine with the copper electrode in water remain unclear, posing challenges in the prediction and optimization of reaction outcomes.
View Article and Find Full Text PDFStructure-guided design and synthesis of C22- and C32-modified FK520 analogs with enhanced activity against human pathogenic fungi.
Proc Natl Acad Sci U S A
January 2025
Department of Chemistry, Duke University, Durham, NC 27708.
Invasive fungal infections are a leading cause of death worldwide. Translating molecular insights into clinical benefits is challenging because fungal pathogens and their hosts share similar eukaryotic physiology. Consequently, current antifungal treatments have limited efficacy, may be poorly fungicidal in the host, can exhibit toxicity, and are increasingly compromised by emerging resistance.
View Article and Find Full Text PDFAmorphous Carbon Monolayer: A van der Waals Interface for High-Performance Metal Oxide Semiconductor Devices.
ACS Nano
December 2024
Department of Materials Science and Engineering, Hanbat National University, Daejeon 34158, Republic of Korea.
Ultrasmall-scale semiconductor devices (≤5 nm) are advancing technologies, such as artificial intelligence and the Internet of Things. However, the further scaling of these devices poses critical challenges, such as interface properties and oxide quality, particularly at the high-/semiconductor interface in metal-oxide-semiconductor (MOS) devices. Existing interlayer (IL) methods, typically exceeding 1 nm thickness, are unsuitable for ultrasmall-scale devices.
View Article and Find Full Text PDFBreaking the Ice: Hofmeister Effect-Inspired Hydrogen Bond Network Reconstruction in Hydrogel Electrolytes for High-Performance Zinc-Ion Batteries.
Small
December 2024
State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China.
Gel electrolytes have emerged as a promising solution for enhancing the performance of zinc-ion batteries (ZIBs), particularly in flexible devices. However, they face challenges such as low-temperature inefficiency, constrained ionic conductivity, and poor mechanical strength. To address these issues, this study presents a novel PAMCD gel electrolyte with tunable freezing point and mechanical properties for ZIBs, blending the high ionic conductivity of polyacrylamide with the anion interaction capability of β-cyclodextrin.
View Article and Find Full Text PDFCellulose nanofibril enhanced ionic conductive hydrogels with high stretchability, high toughness and self-adhesive ability for flexible strain sensors.
Int J Biol Macromol
December 2024
State Key Laboratory of Metastable Materials Science and Technology, Hebei Key Laboratory of Applied Chemistry, Hebei Key Laboratory of Nanobiotechnology, Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse, Yanshan University, Qinhuangdao 066004, China. Electronic address:
Preparation of ion-conductive hydrogels with excellent mechanics, good conductivity and adhesiveness is promising for flexible sensors, but remains a challenge. Here, we prepare a self-adhesive and ion-conductive hydrogel by introducing cellulose nanofibers (CNF) and ZnSO into a covalently-crosslinked poly (acrylamide-co-2-acrylamide-2-methyl propane sulfonic acid) (P(AM-co-AMPS)) network. Owing to the hydrogen bonding and metal coordination interactions among P(AM-co-AMPS) chains, CNF, and Zn, the resulting P(AM-co-AMPS)/CNF/ZnSO hydrogel exhibits high stretchability (1092 %), high toughness (244 kJ m), and skin-like elasticity (3.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!