Subtle Differences in Active Site Structure between Bovine and Human Thrombins: ESR and Fluorescence Studies

1991 ◽  
Vol 65 (01) ◽  
pp. 040-045 ◽  
Author(s):  
Vicki L Nienaber ◽  
Lawrence J Berliner
Keyword(s):  
Ligand Binding ◽  
Active Site ◽  
Hydrophobic Interactions ◽  
Bovine Thrombin ◽  
Site Structure ◽  
X Ray ◽  
Fluorescence Studies ◽  
Human Thrombin ◽  
Active Site Structure ◽  
Protein Active Site

SummaryThe primary structures of bovine and human a-thrombins are highly homologous yet their x-ray structures are not yet complete enough to distinguish differences. In order to probe and compare their dynamic conformations in solution, we examined bovine and human α-thombins with a series of active site directed fluorosul-fonylphenyl spin labeled inhibitors and fluorophores which probe a region within 10-15 Å of the catalytic serine residue. Overall, the nitroxide moieties were more immobilized in the bovine vs human derivatives reflecting either more apolar binding regions or steric obstructions to the motion of the nitroxide in bovine thrombin. Most of the labels which distinguish indole (apolar ligand) binding in human thrombin were found to display similar interactions in bovine thrombin, although slight differences in the general topography of this region were suggested. The two active site directed fluorophores, dansyl fluoride and p-nitrophenyl anthranilate showed differences in both λem max and λex max of the complexes with bovine and human-a-thrombin, respectively. Several of the effects observed i.e., ligand binding (indole or benzamidine) and the subtle hydrophobic interactions between the nitroxide moiety and the protein active site would be difficult to assess from an x-ray structure determination alone.

Active site structure and catalytic mechanisms of human peroxidases

2006 ◽  
Vol 445 (2) ◽  
pp. 199-213 ◽  
Author(s):  
Paul G. Furtmüller ◽  
Martina Zederbauer ◽  
Walter Jantschko ◽  
Jutta Helm ◽  
Martin Bogner ◽  
...  
Keyword(s):  
Active Site ◽  
Site Structure ◽  
Active Site Structure ◽  
Catalytic Mechanisms

scholarly journals Iron-Imprinted Single-Atomic Site Catalyst-Based Nanoprobe for Detection of Hydrogen Peroxide in Living Cells

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhaoyuan Lyu ◽  
Shichao Ding ◽  
Maoyu Wang ◽  
Xiaoqing Pan ◽  
Zhenxing Feng ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Active Site ◽  
Single Atom ◽  
Site Structure ◽  
Atomic Site ◽  
Ion Imprinting ◽  
Active Site Structure ◽  
In Situ Detection ◽  
Colorimetric Biosensing

AbstractFe-based single-atomic site catalysts (SASCs), with the natural metalloproteases-like active site structure, have attracted widespread attention in biocatalysis and biosensing. Precisely, controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs’ performance. In this work, we use a facile ion-imprinting method (IIM) to synthesize isolated Fe-N-C single-atomic site catalysts (IIM-Fe-SASC). With this method, the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites. The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references. Due to its excellent properties, IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide (H2O2). Using IIM-Fe-SASC as the nanoprobe, in situ detection of H2O2 generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity. This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H2O2 detection.

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