
TY  - JOUR
A1  - Pike, Carl S. 
A1  - Grieve, Joanne 
A1  - Badger, Murray R. 
A1  - Price, G. Dean 
T1  - Thermoprotective properties of small heat shock proteins from rice, tomato and <emph type="2">Synechocystis</emph> sp. PCC6803 overexpressed in, and isolated from, <emph type="2">Escherichia coli</emph>
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2001
VL  - 28
IS  - 12
SP  - 1219
EP  - 1229
KW  - 
UR  - https://doi.org/10.1071/PP01107 
N2  - The present study forms part of a program investigating the role of small heat shock proteins (sHSPs) in the acquired and transgenic thermotolerance of the cyanobacterium Synechococcus PCC7942. The genes for three minimally related sHSPs, OsHSP from Oryza sativacytoplasm, tom111 from Lycopersicon esculentumchloroplasts, and 6803 HSP from Synechocystis sp. PCC6803, were cloned into the Escherichia coli vector pTrcHisA, so as to produce an N-terminal polyhistidine tag. The genes were transformed into E. coli and overexpressed. The tagged HSPs were purified (not completely in the case of tom111) by immobilised metal affinity chromatography. The native proteins exhibited a high degree of oligomerisation when analysed by size-exclusion chromatography. All three proteins were able to protect malate dehydrogenase (MDH) from in vitro thermal aggregation. They could also protect several soluble proteins in E. coli extracts from thermal aggregation in vitro, as well as protecting phycocyanin in extracts from Synechococcus sp. PCC7942. None of the proteins were able to protect photosystem II (measured as &Phi;PSII, the effective quantum fluorescence yield of PSII) of thylakoids isolated from Synechococcus sp. PCC7942 from heat damage in vitro, although in vivo, after acclimation, photosystem II did exhibit acquired thermotolerance. 
ER  -

