Characterization of a family of ice-active proteins from the Ryegrass, Lolium perenne.
Five genes coding for ice-active proteins were identified from an expressed sequence tag database of Lolium perenne cDNA libraries. Each of the five genes were characterized by the presence of an N-terminal signal peptide, a region enriched in hydrophilic amino acids and a leucine-rich region in four of the five genes that is homologous with the receptor domain of receptor-like protein kinases of plants. The C-terminal region of all five genes contains sequence homologous with Lolium and Triticum ice-active proteins. Of the four ice-active proteins (IAP1, IAP2, IAP3 and IAP5) cloned, three could be expressed in Escherichia coli and recovered in a functional form in order to study their ice activity. All three ice-active proteins had recrystallization inhibition activity but showed no detectable antifreeze or ice nucleation activity at the concentration tested. IAP2 and IAP5 formed distinct hexagonal-shaped crystals in the nanolitre osmometer as compared to the weakly hexagonal crystals produced by IAP3.
Kumble
Krishnanand D
KD
Genesis Research and Development Corporation Limited, Parnell, Auckland 1052, New Zealand.
Demmer
Jerome
J
Fish
Steven
S
Hall
Claire
C
Corrales
Sofia
S
DeAth
Angela
A
Elton
Clare
C
Prestidge
Ross
R
Luxmanan
Selvanesan
S
Marshall
Craig J
CJ
Wharton
David A
DA
D021301:Antifreeze Proteins / Q000378:metabolism; D003460:Crystallization; D005615:Freezing; D006361:Heating; D007053:Ice; D008129:Lolium / Q000235:genetics* / Q000378:metabolism*; D009994:Osmolar Concentration; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D021301:Antifreeze Proteins; D007053:Ice; D010940:Plant Proteins; D011994:Recombinant Proteins