The thermal hysteresis activity of the type I antifreeze protein: A statistical mechanics model

2009 ◽  
Vol 472 (1-3) ◽  
pp. 124-127 ◽  
Author(s):  
Li-Fen Li ◽  
X.X. Liang ◽  
Q.Z. Li
Keyword(s):  
Statistical Mechanics ◽  
Thermal Hysteresis ◽  
Protein A ◽  
Antifreeze Protein ◽  
Type I ◽  
Thermal Hysteresis Activity ◽  
Mechanics Model

The Thermal Hysteresis of the Type I Antifreeze Protein ‘HPLC-6’: The Effect of Small System

2013 ◽  
Vol 658 ◽  
pp. 169-173
Author(s):  
Li Fen Li ◽  
Xi Xia Liang
Keyword(s):  
Thermal Hysteresis ◽  
Antifreeze Protein ◽  
Type I ◽  
Small System ◽  
Thermal Hysteresis Activity

According to Hill’s thermodynamics theory for small system, the effect of small system on the thermal hysteresis activity of type I antifreeze protein ‘HPLC-6’ is discussed in this article. We conclude that when the solution is very dilute, the effect is not visible, and as the concentration increases, the effect becomes more visible than before, and the result also shows that the thermal hysteresis temperature becomes larger when the effect of small system is considered.

scholarly journals Significance of conservative asparagine residues in the thermal hysteresis activity of carrot antifreeze protein

2004 ◽  
Vol 377 (3) ◽  
pp. 589-595 ◽  
Author(s):  
Dang-Quan ZHANG ◽  
Bing LIU ◽  
Dong-Ru FENG ◽  
Yan-Ming HE ◽  
Shu-Qi WANG ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Tandem Repeat ◽  
Thermal Hysteresis ◽  
Three Dimensional ◽  
Antifreeze Protein ◽  
Three Dimensional Model ◽  
Prism Plane ◽  
Thermal Hysteresis Activity ◽  
Ice Binding

The ~24-amino-acid leucine-rich tandem repeat motif (PXXXXXLXXLXXLXLSXNXLXGXI) of carrot antifreeze protein comprises most of the processed protein and should contribute at least partly to the ice-binding site. Structural predictions using publicly available online sources indicated that the theoretical three-dimensional model of this plant protein includes a 10-loop β-helix containing the ~24-amino-acid tandem repeat. This theoretical model indicated that conservative asparagine residues create putative ice-binding sites with surface complementarity to the 1010 prism plane of ice. We used site-specific mutagenesis to test the importance of these residues, and observed a distinct loss of thermal hysteresis activity when conservative asparagines were replaced with valine or glutamine, whereas a large increase in thermal hysteresis was observed when phenylalanine or threonine residues were replaced with asparagine, putatively resulting in the formation of an ice-binding site. These results confirmed that the ice-binding site of carrot antifreeze protein consists of conservative asparagine residues in each β-loop. We also found that its thermal hysteresis activity is directly correlated with the length of its asparagine-rich binding site, and hence with the size of its ice-binding face.

scholarly journals Isolation and characterization of a novel antifreeze protein from carrot (Daucus carota)

1999 ◽  
Vol 340 (2) ◽  
pp. 385-391 ◽  
Author(s):  
Maggie SMALLWOOD ◽  
Dawn WORRALL ◽  
Louise BYASS ◽  
Luisa ELIAS ◽  
David ASHFORD ◽  
...  
Keyword(s):  
Plant Extracts ◽  
Daucus Carota ◽  
Thermal Hysteresis ◽  
Antifreeze Protein ◽  
Ice Recrystallization ◽  
Thermal Hysteresis Activity ◽  
Isolation And Characterization ◽  
Tap Root ◽  
Unequivocal Identification

A modified assay for inhibition of ice recrystallization which allows unequivocal identification of activity in plant extracts is described. Using this assay a novel, cold-induced, 36 kDa antifreeze protein has been isolated from the tap root of cold-acclimated carrot (Daucus carota) plants. This protein inhibits the recrystallization of ice and exhibits thermal-hysteresis activity. The polypeptide behaves as monomer in solution and is N-glycosylated. The corresponding gene is unique in the carrot genome and induced by cold. The antifreeze protein appears to be localized within the apoplast.

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