scholarly journals Role of changes in the L3 loop of the active site in the evolution of enzymatic activity of VIM-type metallo- -lactamases

2010 ◽  
Vol 65 (9) ◽  
pp. 1950-1954 ◽  
Author(s):  
M. Merino ◽  
F. J. Perez-Llarena ◽  
F. Kerff ◽  
M. Poza ◽  
S. Mallo ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Active Site

scholarly journals Comment on: Role of changes in the L3 loop of the active site in the evolution of enzymatic activity of VIM-type metallo- -lactamases

2010 ◽  
Vol 66 (3) ◽  
pp. 684-685 ◽  
Author(s):  
M. Castanheira ◽  
L. M. Deshpande ◽  
R. E. Mendes ◽  
E. Rodriguez-Noriega ◽  
R. N. Jones ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Active Site

Temperature Sensitivity of Myosin and Actomyosin

1973 ◽  
Vol 51 (1) ◽  
pp. 71-86 ◽  
Author(s):  
A. L. Jacobson ◽  
J. Henderson
Keyword(s):  
Enzymatic Activity ◽  
Conformational Changes ◽  
Temperature Sensitivity ◽  
Active Site ◽  
Temperature Effects ◽  
Thermal Denaturation ◽  
Site Analysis ◽  
Maximum Change ◽  
Temperature Inactivation

The thermal denaturation of myosin and actomyosin was studied by active site analysis (enzymatic activity) and measurements were related to overall conformational changes (viscosity) over the temperature range 19–65 °C. The role of sulfhydryl (SH) groups on the temperature-induced denaturation of actomyosin was investigated. The temperature of maximum change in the overall conformation (the melting temperature, TM) was unaffected by the binding of F-actin to myosin. For both myosin and actomyosin the TM was 43 ± 2 °C. However, the range of temperature over which large conformational changes were observed was affected by the binding of F-actin to myosin. For myosin and dissociated actomyosin, changes were observed between 37 and 50 °C, while for actomyosin large changes were observed between 20 and 50 °C. With actomyosin there was an irreversible increase in titratable sulfhydryl groups from 19 to 60 °C. Temperature effects on the calcium-activated ATPase were studied. The temperature of maximum enzymatic activity for actomyosin was 45 ± 2 °C, which corresponds to the TM and the temperature at which increases in SH content were apparent. However, for myosin the temperature of maximum enzymatic activity was 33 °C, considerably below the TM. Overall conformational changes were reversible below the TM, while changes in enzymatic activity were reversible below the temperature of maximum enzymatic activity. Actin offers considerable protection to the temperature inactivation of the active site of myosin even though the F-actin–myosin complex is very highly dissociated in the presence of ATP. However, there is no significant stabilization of myosin by F-actin in terms of the temperature sensitivity of the overall conformation.

scholarly journals Role of changes in the L3 loop of the active site in the evolution of enzymatic activity of VIM-type metallo- -lactamases--authors' response

2010 ◽  
Vol 66 (3) ◽  
pp. 686-686 ◽  
Author(s):  
M. Merino ◽  
F. J. Perez-Llarena ◽  
F. Kerff ◽  
M. Poza ◽  
S. Mallo ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Active Site

scholarly journals Potential Dual Role of West Nile Virus NS2B in Orchestrating NS3 Enzymatic Activity in Viral Replication

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 216
Author(s):  
Alanna C. Tseng ◽  
Vivek R. Nerurkar ◽  
Kabi R. Neupane ◽  
Helmut Kae ◽  
Pakieli H. Kaufusi
Keyword(s):  
West Nile Virus ◽  
Enzymatic Activity ◽  
Nonstructural Protein ◽  
Antiviral Drug ◽  
West Nile ◽  
Biochemical Assays ◽  
In Trans ◽  
Viral Polyprotein ◽  
Ns3 Protease

West Nile virus (WNV) nonstructural protein 3 (NS3) harbors the viral triphosphatase and helicase for viral RNA synthesis and, together with NS2B, constitutes the protease responsible for polyprotein processing. NS3 is a soluble protein, but it is localized to specialized compartments at the rough endoplasmic reticulum (RER), where its enzymatic functions are essential for virus replication. However, the mechanistic details behind the recruitment of NS3 from the cytoplasm to the RER have not yet been fully elucidated. In this study, we employed immunofluorescence and biochemical assays to demonstrate that NS3, when expressed individually and when cleaved from the viral polyprotein, is localized exclusively to the cytoplasm. Furthermore, NS3 appeared to be peripherally recruited to the RER and proteolytically active when NS2B was provided in trans. Thus, we provide evidence for a potential additional role for NS2B in not only serving as the cofactor for the NS3 protease, but also in recruiting NS3 from the cytoplasm to the RER for proper enzymatic activity. Results from our study suggest that targeting the interaction between NS2B and NS3 in disrupting the NS3 ER localization may be an attractive avenue for antiviral drug discovery.

Exploring the Role of the Central Carbide of the Nitrogenase Active-Site FeMo-cofactor through Targeted 13C Labeling and ENDOR Spectroscopy

2021 ◽  
Author(s):  
Ana Pérez-González ◽  
Zhi-Yong Yang ◽  
Dmitriy A. Lukoyanov ◽  
Dennis R. Dean ◽  
Lance C. Seefeldt ◽  
...  
Keyword(s):  
Active Site ◽  
13C Labeling ◽  
Endor Spectroscopy ◽  
Femo Cofactor

Protein Immobilization in Metal–Organic Frameworks by Covalent Binding

2014 ◽  
Vol 67 (11) ◽  
pp. 1629 ◽  
Author(s):  
Xuan Wang ◽  
Trevor A. Makal ◽  
Hong-Cai Zhou
Keyword(s):  
Enzymatic Activity ◽  
Enzyme Immobilization ◽  
Working Conditions ◽  
Active Site ◽  
Covalent Binding ◽  
Metal Organic Frameworks ◽  
Protein Immobilization ◽  
Immobilization Of Enzymes ◽  
Metal Organic ◽  
Biological Catalysis

Metal–organic frameworks (MOFs), possessing a well defined system of pores, demonstrate extensive potential serving as a platform in biological catalysis. Successful immobilization of enzymes in a MOF system retains the enzymatic activity, renders the active site more accessible to the substrate, and promises recyclability for reuse, and solvent adaptability in a broad range of working conditions. This highlight describes enzyme immobilization on MOFs via covalent binding and its significance.

scholarly journals The Role of Active Site Arginines of Sorghum NADP-Malate Dehydrogenase in Thioredoxin-dependent Activation and Activity

2000 ◽  
Vol 275 (46) ◽  
pp. 35792-35798 ◽  
Author(s):  
Isabelle Schepens ◽  
Eric Ruelland ◽  
Myroslawa Miginiac-Maslow ◽  
Pierre Le Maréchal ◽  
Paulette Decottignies
Keyword(s):  
Malate Dehydrogenase ◽  
Active Site
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