The angiotensin I-converting enzyme (ACE) converts the decapeptide angiotensin I (Ang I) into angiotensin II by releasing the C-terminal dipeptide. A novel approach combining enzymatic and electron paramagnetic resonance (EPR) studies was developed to determine the enzyme effect on Ang I containing the paramagnetic 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (TOAC) at positions 1, 3, 8, and 9. Biological assays indicated that TOAC(1)-Ang I maintained partly the Ang I activity, and that only this derivative and the TOAC(3)-Ang I were cleaved by ACE. Quenching of Tyr(4) fluorescence by TOAC decreased with increasing distance between both residues, suggesting an overall partially extended structure. However, the local bend known to be imposed by the substituted diglycine TOAC is probably responsible for steric hindrance, not allowing the analogues containing TOAC at positions 8 and 9 to act as substrates. In some cases, although substrates and products differ by only two residues, the difference between their EPR spectral lineshapes allows monitoring the enzymatic reaction as a function of time.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.febslet.2007.04.058 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Determining the helical tilt angle and dynamic properties of the transmembrane domains of pinholin S68 using mechanical alignment EPR spectroscopy.
Biochim Biophys Acta Biomembr
June 2023
Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA. Electronic address:
The lytic cycle of bacteriophage φ21 for the infected E. coli is initiated by pinholin S, which determines the timing of host cell lysis through the function of pinholin (S68) and antipinholin (S71). The activity of pinholin or antipinholin directly depends on the function of two transmembrane domains (TMDs) within the membrane.
View Article and Find Full Text PDFBredemolic acid restores glucose utilization and attenuates oxidative stress in palmitic acid-induced insulin-resistant C2C12 cells.
Endocr Regul
April 2022
Department of Physiology, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, College of Health Sciences, Durban, South Africa.
Due to insulin resistance and oxidative stress that are associated with type 2 diabetes mellitus (T2DM), T2DM has become a prevalent metabolic disorder that presents various side effects. However, alternative antidiabetic treatment has commonly been used in treating diabetes mellitus in diabetic patients. In our previous studies, bredemolic acid has been reported as an antidiabetic agent that improves glucose uptake, ameliorates insulin resistance, and oxidative stress in the liver, heart, kidney, and skeletal muscle of prediabetic rats.
View Article and Find Full Text PDFIs Cys(MTSL) the Best α-Amino Acid Residue to Electron Spin Labeling of Synthetically Accessible Peptide Molecules with Nitroxides?
ACS Omega
February 2022
Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russian Federation.
Electron paramagnetic resonance spectroscopy, particularly its pulse technique double electron-electron resonance (DEER) (also termed PELDOR), is rapidly becoming an extremely useful tool for the experimental determination of side chain-to-side chain distances between free radicals in molecules fundamental for life, such as polypeptides. Among appropriate probes, the most popular are undoubtedly nitroxide electron spin labels. In this context, suitable biosynthetically derived, helical regions of proteins, along with synthetic peptides with amphiphilic properties and antibacterial activities, are the most extensively investigated compounds.
View Article and Find Full Text PDFTOAC spin-labeled peptides tailored for DNP-NMR studies in lipid membrane environments.
Biophys J
October 2021
School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia. Electronic address:
The benefit of combining in-cell solid-state dynamic nuclear polarization (DNP) NMR and cryogenic temperatures is providing sufficient signal/noise and preservation of bacterial integrity via cryoprotection to enable in situ biophysical studies of antimicrobial peptides. The radical source required for DNP was delivered into cells by adding a nitroxide-tagged peptide based on the antimicrobial peptide maculatin 1.1 (Mac1).
View Article and Find Full Text PDFProbing the E/K Peptide Coiled-Coil Assembly by Double Electron-Electron Resonance and Circular Dichroism.
Biochemistry
January 2021
Novosibirsk State University, Novosibirsk 630090, Russian Federation.
Double electron-electron resonance (DEER, also known as PELDOR) and circular dichroism (CD) spectroscopies were explored for the purpose of studying the specificity of the conformation of peptides induced by their assembly into a self-recognizing system. The E and K peptides are known to form a coiled-coil heterodimer. Two paramagnetic TOAC α-amino acid residues were incorporated into each of the peptides (denoted as K** and E**), and a three-dimensional structural investigation in the presence or absence of their unlabeled counterparts E and K was performed.
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!