Thermal Transfer from the Surface Loop to the Iron Active Site of Soybean Lipoxygenase

6-Pentadecanylsalicylic acid, referred to as anacardic acid (C15:0), was found to inhibit the linoleic acid peroxidation competitively catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, Type 1) with an IC50 of 14.3 μM (4.88 μg/mL). This inhibition is a reversible reaction without pro-oxidant effects. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:0) is a competitive inhibitor and the inhibition constant, KI, was established as 6.4 μM. The hydrophilic head (salicylic acid) portion first chelates the iron in the active site and then the hydrophobic tail portion begins reversibly interacting with the C-terminal domain where the iron is located. The inhibition of anacardic acid (C15:0) can be explained by a combination of iron ion-chelation and hydrophobic interaction abilities because of its specific structural feature.

Download Full-text

Gauging the Flexibility of the Active Site in Soybean Lipoxygenase-1 (SLO-1) through an Atom-Centered Density Matrix Propagation (ADMP) Treatment That Facilitates the Sampling of Rare Events

The Journal of Physical Chemistry B ◽

10.1021/jp3015047 ◽

2012 ◽

Vol 116 (34) ◽

pp. 10145-10164 ◽

Cited By ~ 16

Author(s):

Prasad Phatak ◽

Isaiah Sumner ◽

Srinivasan S. Iyengar

Keyword(s):

Density Matrix ◽

Active Site ◽

Rare Events ◽

Soybean Lipoxygenase

Download Full-text

Phosphate binding in the active centre of tomato multifunctional nuclease TBN1 and analysis of superhelix formation by the enzyme

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x15018324 ◽

2015 ◽

Vol 71 (11) ◽

pp. 1408-1415 ◽

Cited By ~ 1

Author(s):

Jan Stránský ◽

Tomáš Koval' ◽

Tomáš Podzimek ◽

Anna Týcová ◽

Petra Lipovová ◽

...

Keyword(s):

Active Site ◽

Phosphate Buffer ◽

Crystal Packing ◽

Cell Senescence ◽

Regulatory Function ◽

Type I ◽

Phosphate Binding ◽

Active Centre ◽

Surface Loop ◽

Phosphate Ion

Tomato multifunctional nuclease TBN1 belongs to the type I nuclease family, which plays an important role in apoptotic processes and cell senescence in plants. The newly solved structure of the N211D mutant is reported. Although the main crystal-packing motif (the formation of superhelices) is conserved, the details differ among the known structures. A phosphate ion was localized in the active site of the enzyme. The binding of the surface loop to the active centre is stabilized by the phosphate ion, which correlates with the observed aggregation of TBN1 in phosphate buffer. The conserved binding of the surface loop to the active centre suggests biological relevance of the contact in a regulatory function or in the formation of oligomers.

Download Full-text