Fish, antifreeze proteins

Polyamino acids or + tetrapentylammonium bromide Poly-L-proline (related to fish antifreeze protein) RF (Rogaland Research) ... 

Arabidopsis Kinl" Similarities to a fish antifreeze protein ABA, water stress Kurkela Franck, 1990... 

Figure 4 Inhibition of ice recrystallization. Samples in 10 pi microcapillaries (740 pm diameter) were frozen and placed at -6°C and examined between crossed polarizing filters. Images were taken prior to, and after overnight incubation, but only the latter images are shown. From left to right samples include sample buffer controls (I, 2), bovine serum albumin, a control protein diluted to 0.2 and 0.02 mg/ ml, respectively (3,4), serial dilutions of 0.2, 0.02 and 0.002 mg/ ml Type I fish antifreeze protein in buffer (5-7), Chryseobacterium sp. cultures (8, 9), and E. coli cultures (10, 11). Note that only the fish AFP and the Chryseobacterium sp. cidtures have crystals too small to be detected at this magnification and the overlying feathery pattern, typical of snap frozen samples, is apparent. Bacterial cultures were at 2 x 10 CFU/ ml. Lines indicate duplicate samples and arrows indicate samples that were diluted.

Graether SP, Slupsky CM, Sykes BD (2003) Freezing of a fish antifreeze protein results in amyloid fibril... 

Type I threonine-rich fish antifreeze protein [528]... 

K.V. Ewart, B. Rubinsky, and G.L. Fletcher, Structural and functional similarity between fish antifreeze proteins and calcium-dependent lectins, Biochem. Biophys. Res. Commun., 185 (1992) 335. 

Antifreeze Protein from Fish Bloods Robert E. Feekney and Yin Yeh... 

Fish living in Arctic and Antarctic waters may encounter temperatures as low as -1.9°C. The freezing point depression provided by dissolved salts and proteins in the blood is insufficient to protect the fish from freezing. As winter approaches, they synthesize and accumulate in their blood serum a series of eight or more special antifreeze proteins.a d One type of antifreeze glycoprotein from winter flounder contains the following unit repeated 17-50 times. 

Antifreeze proteins, that are 3-4 times as effective as those in fish, have been isolated from some insects and other arthropods.1 11 0 They help beetle larvae to overwinter. The insect proteins have a parallel P helix structure resembling that in Fig. 2-17 and stabilized by S — S bridges.0 Some plants also synthesize antifreeze proteins.11 1 One of these, isolated from carrots, is a member of the leucine-rich-repeat family ... 

Antifreeze proteins (AFPs) are ice-binding proteins found in some organisms (such as fish, insects, plants and soil bacteria) that live at the temperature of their surroundings and encounter freezing conditions. AFPs help organisms to survive below 0°C by inhibiting ice growth. AFPs are structurally diverse, each is radically different from the others in its primary,... 

Baardsnes, J. and Davies, P.L. 2002. Contribution of hydrophobic residues to ice binding by fish type III antifreeze protein. Biochim. Biophys. Acta 1601, 49-54. 

Figure 7.39. The diversity of antifreeze proteins and antifreeze glycoproteins in marine fishes. Shown are the structures of four types of AFPs (I-IV) and the AFGP found in Antarctic notothenioids and Arctic cod. AFPs I-IV are shown as ribbon structures. The tripeptide repeat (-ala-ala-thr-) and carbohydrate moiety (galactosyl-lV-acetylgalactosamine) of AFGPs illustrate the key element of AFGP structures in noto-thenioid and Arctic cod.

Fletcher, G.L., C.L. Hew, X. Li, K. Haya, and M.H. Kao (1985). Year-round presence of high levels of plasma antifreeze proteins in a temperate fish, ocean pout (Macrozoarces americanus). Can. J. Zool. 63 488-493. 

The 0-linked saccharides are not as common as the A-linked saccharides. A relatively simple saccharide is that attached to L-threonine of the highly glyosylated (1 out of every 3 amino acid residues), antifreeze protein found in the blood sera of fish living in the Arctic and Antarctic waters. This glycoside is a disaccharide, -D-Galp-(1 3)-cz-D-GalNAc p [147]. 

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